diff --git a/contrib/single_file_libs/combine.sh b/contrib/single_file_libs/combine.sh
index ea99717f8..05c7bce8e 100755
--- a/contrib/single_file_libs/combine.sh
+++ b/contrib/single_file_libs/combine.sh
@@ -41,11 +41,15 @@ usage() {
 }
 
 # Tests that the grep implementation works as expected (older OSX grep fails)
-test_grep() {
+test_deps() {
   if ! echo '#include "foo"' | grep -Eq '^\s*#\s*include\s*".+"'; then
     echo "Aborting: the grep implementation fails to parse include lines"
     exit 1
   fi
+  if ! echo '"foo.h"' | sed -E 's/"([^"]+)"/\1/' | grep -Eq '^foo\.h$'; then
+    echo "Aborting: sed is unavailable or non-functional"
+    exit 1
+  fi
 }
 
 # Tests if list $1 has item $2 (returning zero on a match)
@@ -66,41 +70,75 @@ write_line() {
   fi
 }
 
-# Adds the contents of $1 with any of its includes inlined
-add_file() {
-  # Match the path
-  local file=
-  for root in $ROOTS; do
-    if [ -f "$root/$1" ]; then
-      file="$root/$1"
+log_line() {
+  echo $@ >&2
+}
+
+# Find this file!
+resolve_include() {
+  local srcdir=$1
+  local inc=$2
+  for root in $srcdir $ROOTS; do
+    if [ -f "$root/$inc" ]; then
+      # Try to reduce the file path into a canonical form (so that multiple)
+      # includes of the same file are successfully deduplicated, even if they
+      # are expressed differently.
+      local relpath="$(realpath --relative-to . "$root/$inc" 2>/dev/null)"
+      if [ "$relpath" != "" ]; then # not all realpaths support --relative-to
+        echo "$relpath"
+        return 0
+      fi
+      local relpath="$(realpath "$root/$inc" 2>/dev/null)"
+      if [ "$relpath" != "" ]; then # not all distros have realpath...
+        echo "$relpath"
+        return 0
+      fi
+      # Worst case, fall back to just the root + relative include path. The
+      # problem with this is that it is possible to emit multiple different
+      # resolved paths to the same file, depending on exactly how its included.
+      # Since the main loop below keeps a list of the resolved paths it's
+      # already included, in order to avoid repeated includes, this failure to
+      # produce a canonical/reduced path can lead to multiple inclusions of the
+      # same file. But it seems like the resulting single file library still
+      # works (hurray include guards!), so I guess it's ok.
+      echo "$root/$inc"
+      return 0
     fi
   done
+  return 1
+}
+
+# Adds the contents of $1 with any of its includes inlined
+add_file() {
+  local file=$1
   if [ -n "$file" ]; then
-    if [ -n "$DESTN" ]; then
-      # Log but only if not writing to stdout
-      echo "Processing: $file"
-    fi
+    log_line "Processing: $file"
+    # Get directory of the current so we can resolve relative includes
+    local srcdir="$(dirname "$file")"
     # Read the file
     local line=
     while IFS= read -r line; do
       if echo "$line" | grep -Eq '^\s*#\s*include\s*".+"'; then
         # We have an include directive so strip the (first) file
-        local inc=$(echo "$line" | grep -Eo '".*"' | grep -Eo '\w*(\.?\w+)+' | head -1)
+        local inc=$(echo "$line" | grep -Eo '".*"' | sed -E 's/"([^"]+)"/\1/' | head -1)
+        local res_inc="$(resolve_include "$srcdir" "$inc")"
         if list_has_item "$XINCS" "$inc"; then
           # The file was excluded so error if the source attempts to use it
           write_line "#error Using excluded file: $inc"
+          log_line "Excluding: $inc"
         else
-          if ! list_has_item "$FOUND" "$inc"; then
+          if ! list_has_item "$FOUND" "$res_inc"; then
             # The file was not previously encountered
-            FOUND="$FOUND $inc"
+            FOUND="$FOUND $res_inc"
             if list_has_item "$KINCS" "$inc"; then
               # But the include was flagged to keep as included
               write_line "/**** *NOT* inlining $inc ****/"
               write_line "$line"
+              log_line "Not Inlining: $inc"
             else
               # The file was neither excluded nor seen before so inline it
               write_line "/**** start inlining $inc ****/"
-              add_file "$inc"
+              add_file "$res_inc"
               write_line "/**** ended inlining $inc ****/"
             fi
           else
@@ -122,6 +160,7 @@ add_file() {
     done < "$file"
   else
     write_line "#error Unable to find \"$1\""
+    log_line "Error: Unable to find: \"$1\""
   fi
 }
 
@@ -154,8 +193,8 @@ if [ -n "$1" ]; then
     if [ -n "$DESTN" ]; then
       printf "" > "$DESTN"
     fi
-    test_grep
-    add_file $1
+    test_deps
+    add_file "$1"
   else
     echo "Input file not found: \"$1\""
     exit 1
diff --git a/contrib/single_file_libs/create_single_file_decoder.sh b/contrib/single_file_libs/create_single_file_decoder.sh
index ad249ccd7..b5f5613ae 100755
--- a/contrib/single_file_libs/create_single_file_decoder.sh
+++ b/contrib/single_file_libs/create_single_file_decoder.sh
@@ -5,7 +5,7 @@ ZSTD_SRC_ROOT="../../lib"
 
 # Amalgamate the sources
 echo "Amalgamating files... this can take a while"
-./combine.sh -r "$ZSTD_SRC_ROOT" -r "$ZSTD_SRC_ROOT/common" -r "$ZSTD_SRC_ROOT/decompress" -o zstddeclib.c zstddeclib-in.c
+./combine.sh -r "$ZSTD_SRC_ROOT" -o zstddeclib.c zstddeclib-in.c
 # Did combining work?
 if [ $? -ne 0 ]; then
   echo "Combine script: FAILED"
diff --git a/contrib/single_file_libs/create_single_file_library.sh b/contrib/single_file_libs/create_single_file_library.sh
index 68bbfbd27..6cbff4595 100755
--- a/contrib/single_file_libs/create_single_file_library.sh
+++ b/contrib/single_file_libs/create_single_file_library.sh
@@ -5,7 +5,7 @@ ZSTD_SRC_ROOT="../../lib"
 
 # Amalgamate the sources
 echo "Amalgamating files... this can take a while"
-./combine.sh -r "$ZSTD_SRC_ROOT" -r "$ZSTD_SRC_ROOT/common" -r "$ZSTD_SRC_ROOT/compress" -r "$ZSTD_SRC_ROOT/decompress"  -k zstd.h -o zstd.c zstd-in.c
+./combine.sh -r "$ZSTD_SRC_ROOT" -k zstd.h -o zstd.c zstd-in.c
 # Did combining work?
 if [ $? -ne 0 ]; then
   echo "Combine script: FAILED"
diff --git a/contrib/single_file_libs/zstd-in.c b/contrib/single_file_libs/zstd-in.c
index c35512264..aa197a682 100644
--- a/contrib/single_file_libs/zstd-in.c
+++ b/contrib/single_file_libs/zstd-in.c
@@ -4,7 +4,7 @@
  *
  * Generate using:
  * \code
- *	combine.sh -r ../../lib -r ../../lib/common -r ../../lib/compress -r ../../lib/decompress -k zstd.h -o zstd.c zstd-in.c
+ *	combine.sh -r ../../lib -k zstd.h -o zstd.c zstd-in.c
  * \endcode
  */
 /*
@@ -46,34 +46,31 @@
 #define ZSTD_MULTITHREAD
 #endif
 
-/* lib/common */
-#include "debug.c"
-#include "entropy_common.c"
-#include "error_private.c"
-#include "fse_decompress.c"
-#include "threading.c"
-#include "pool.c"
-#include "zstd_common.c"
+#include "common/debug.c"
+#include "common/entropy_common.c"
+#include "common/error_private.c"
+#include "common/fse_decompress.c"
+#include "common/threading.c"
+#include "common/pool.c"
+#include "common/zstd_common.c"
 
-/* lib/compress */
-#include "fse_compress.c"
-#include "hist.c"
-#include "huf_compress.c"
-#include "zstd_compress_literals.c"
-#include "zstd_compress_sequences.c"
-#include "zstd_compress_superblock.c"
-#include "zstd_compress.c"
-#include "zstd_double_fast.c"
-#include "zstd_fast.c"
-#include "zstd_lazy.c"
-#include "zstd_ldm.c"
-#include "zstd_opt.c"
+#include "compress/fse_compress.c"
+#include "compress/hist.c"
+#include "compress/huf_compress.c"
+#include "compress/zstd_compress_literals.c"
+#include "compress/zstd_compress_sequences.c"
+#include "compress/zstd_compress_superblock.c"
+#include "compress/zstd_compress.c"
+#include "compress/zstd_double_fast.c"
+#include "compress/zstd_fast.c"
+#include "compress/zstd_lazy.c"
+#include "compress/zstd_ldm.c"
+#include "compress/zstd_opt.c"
 #ifdef ZSTD_MULTITHREAD
-#include "zstdmt_compress.c"
+#include "compress/zstdmt_compress.c"
 #endif
 
-/* lib/decompress */
-#include "huf_decompress.c"
-#include "zstd_ddict.c"
-#include "zstd_decompress.c"
-#include "zstd_decompress_block.c"
+#include "decompress/huf_decompress.c"
+#include "decompress/zstd_ddict.c"
+#include "decompress/zstd_decompress.c"
+#include "decompress/zstd_decompress_block.c"
diff --git a/contrib/single_file_libs/zstddeclib-in.c b/contrib/single_file_libs/zstddeclib-in.c
old mode 100755
new mode 100644
index c447bc25c..a9083dd34
--- a/contrib/single_file_libs/zstddeclib-in.c
+++ b/contrib/single_file_libs/zstddeclib-in.c
@@ -4,7 +4,7 @@
  *
  * Generate using:
  * \code
- *	combine.sh -r ../../lib -r ../../lib/common -r ../../lib/decompress -o zstddeclib.c zstddeclib-in.c
+ *	combine.sh -r ../../lib -o zstddeclib.c zstddeclib-in.c
  * \endcode
  */
 /*
@@ -42,15 +42,13 @@
 #define ZSTD_NOBENCH
 #define ZSTD_STRIP_ERROR_STRINGS
 
-/* lib/common */
-#include "debug.c"
-#include "entropy_common.c"
-#include "error_private.c"
-#include "fse_decompress.c"
-#include "zstd_common.c"
+#include "common/debug.c"
+#include "common/entropy_common.c"
+#include "common/error_private.c"
+#include "common/fse_decompress.c"
+#include "common/zstd_common.c"
 
-/* lib/decompress */
-#include "huf_decompress.c"
-#include "zstd_ddict.c"
-#include "zstd_decompress.c"
-#include "zstd_decompress_block.c"
+#include "decompress/huf_decompress.c"
+#include "decompress/zstd_ddict.c"
+#include "decompress/zstd_decompress.c"
+#include "decompress/zstd_decompress_block.c"
diff --git a/lib/Makefile b/lib/Makefile
index 025de8e54..4e3598acc 100644
--- a/lib/Makefile
+++ b/lib/Makefile
@@ -20,7 +20,7 @@ LIBVER := $(shell echo $(LIBVER_SCRIPT))
 VERSION?= $(LIBVER)
 CCVER := $(shell $(CC) --version)
 
-CPPFLAGS+= -I. -I./common -DXXH_NAMESPACE=ZSTD_
+CPPFLAGS+= -DXXH_NAMESPACE=ZSTD_
 ifeq ($(OS),Windows_NT)   # MinGW assumed
 CPPFLAGS   += -D__USE_MINGW_ANSI_STDIO   # compatibility with %zu formatting
 endif
@@ -149,7 +149,6 @@ ifneq ($(ZSTD_LEGACY_SUPPORT), 0)
 ifeq ($(shell test $(ZSTD_LEGACY_SUPPORT) -lt 8; echo $$?), 0)
 	ZSTD_FILES += $(shell ls legacy/*.c | $(GREP) 'v0[$(ZSTD_LEGACY_SUPPORT)-7]')
 endif
-	CPPFLAGS += -I./legacy
 endif
 CPPFLAGS  += -DZSTD_LEGACY_SUPPORT=$(ZSTD_LEGACY_SUPPORT)
 
diff --git a/lib/common/pool.h b/lib/common/pool.h
index 8503e2d23..259bafc97 100644
--- a/lib/common/pool.h
+++ b/lib/common/pool.h
@@ -18,7 +18,7 @@ extern "C" {
 
 #include <stddef.h>   /* size_t */
 #define ZSTD_STATIC_LINKING_ONLY   /* ZSTD_customMem */
-#include "zstd.h"
+#include "../zstd.h"
 
 typedef struct POOL_ctx_s POOL_ctx;
 
diff --git a/lib/common/zstd_internal.h b/lib/common/zstd_internal.h
index 57a6137e1..bd08de821 100644
--- a/lib/common/zstd_internal.h
+++ b/lib/common/zstd_internal.h
@@ -24,7 +24,7 @@
 #include "debug.h"                 /* assert, DEBUGLOG, RAWLOG, g_debuglevel */
 #include "error_private.h"
 #define ZSTD_STATIC_LINKING_ONLY
-#include "zstd.h"
+#include "../zstd.h"
 #define FSE_STATIC_LINKING_ONLY
 #include "fse.h"
 #define HUF_STATIC_LINKING_ONLY
diff --git a/lib/compress/fse_compress.c b/lib/compress/fse_compress.c
index e09b646df..a42759814 100644
--- a/lib/compress/fse_compress.c
+++ b/lib/compress/fse_compress.c
@@ -17,14 +17,14 @@
 ****************************************************************/
 #include <stdlib.h>     /* malloc, free, qsort */
 #include <string.h>     /* memcpy, memset */
-#include "compiler.h"
-#include "mem.h"        /* U32, U16, etc. */
-#include "debug.h"      /* assert, DEBUGLOG */
+#include "../common/compiler.h"
+#include "../common/mem.h"        /* U32, U16, etc. */
+#include "../common/debug.h"      /* assert, DEBUGLOG */
 #include "hist.h"       /* HIST_count_wksp */
-#include "bitstream.h"
+#include "../common/bitstream.h"
 #define FSE_STATIC_LINKING_ONLY
-#include "fse.h"
-#include "error_private.h"
+#include "../common/fse.h"
+#include "../common/error_private.h"
 
 
 /* **************************************************************
diff --git a/lib/compress/hist.c b/lib/compress/hist.c
index c17b9725f..61e08c796 100644
--- a/lib/compress/hist.c
+++ b/lib/compress/hist.c
@@ -14,9 +14,9 @@
 ****************************************************************** */
 
 /* --- dependencies --- */
-#include "mem.h"             /* U32, BYTE, etc. */
-#include "debug.h"           /* assert, DEBUGLOG */
-#include "error_private.h"   /* ERROR */
+#include "../common/mem.h"             /* U32, BYTE, etc. */
+#include "../common/debug.h"           /* assert, DEBUGLOG */
+#include "../common/error_private.h"   /* ERROR */
 #include "hist.h"
 
 
diff --git a/lib/compress/huf_compress.c b/lib/compress/huf_compress.c
index 4efffbb54..546879868 100644
--- a/lib/compress/huf_compress.c
+++ b/lib/compress/huf_compress.c
@@ -25,14 +25,14 @@
 ****************************************************************/
 #include <string.h>     /* memcpy, memset */
 #include <stdio.h>      /* printf (debug) */
-#include "compiler.h"
-#include "bitstream.h"
+#include "../common/compiler.h"
+#include "../common/bitstream.h"
 #include "hist.h"
 #define FSE_STATIC_LINKING_ONLY   /* FSE_optimalTableLog_internal */
-#include "fse.h"        /* header compression */
+#include "../common/fse.h"        /* header compression */
 #define HUF_STATIC_LINKING_ONLY
-#include "huf.h"
-#include "error_private.h"
+#include "../common/huf.h"
+#include "../common/error_private.h"
 
 
 /* **************************************************************
diff --git a/lib/compress/zstd_compress.c b/lib/compress/zstd_compress.c
index 22f5542eb..ff8a00e6b 100644
--- a/lib/compress/zstd_compress.c
+++ b/lib/compress/zstd_compress.c
@@ -13,13 +13,13 @@
 ***************************************/
 #include <limits.h>         /* INT_MAX */
 #include <string.h>         /* memset */
-#include "cpu.h"
-#include "mem.h"
-#include "hist.h"           /* HIST_countFast_wksp */
+#include "../common/cpu.h"
+#include "../common/mem.h"
+#include "hist.h"       /* HIST_countFast_wksp */
 #define FSE_STATIC_LINKING_ONLY   /* FSE_encodeSymbol */
-#include "fse.h"
+#include "../common/fse.h"
 #define HUF_STATIC_LINKING_ONLY
-#include "huf.h"
+#include "../common/huf.h"
 #include "zstd_compress_internal.h"
 #include "zstd_compress_sequences.h"
 #include "zstd_compress_literals.h"
diff --git a/lib/compress/zstd_compress_internal.h b/lib/compress/zstd_compress_internal.h
index d95eb1bf9..8a16c371a 100644
--- a/lib/compress/zstd_compress_internal.h
+++ b/lib/compress/zstd_compress_internal.h
@@ -18,7 +18,7 @@
 /*-*************************************
 *  Dependencies
 ***************************************/
-#include "zstd_internal.h"
+#include "../common/zstd_internal.h"
 #include "zstd_cwksp.h"
 #ifdef ZSTD_MULTITHREAD
 #  include "zstdmt_compress.h"
diff --git a/lib/compress/zstd_compress_sequences.h b/lib/compress/zstd_compress_sequences.h
index b884e45b4..68c6f9a5a 100644
--- a/lib/compress/zstd_compress_sequences.h
+++ b/lib/compress/zstd_compress_sequences.h
@@ -11,8 +11,8 @@
 #ifndef ZSTD_COMPRESS_SEQUENCES_H
 #define ZSTD_COMPRESS_SEQUENCES_H
 
-#include "fse.h" /* FSE_repeat, FSE_CTable */
-#include "zstd_internal.h" /* symbolEncodingType_e, ZSTD_strategy */
+#include "../common/fse.h" /* FSE_repeat, FSE_CTable */
+#include "../common/zstd_internal.h" /* symbolEncodingType_e, ZSTD_strategy */
 
 typedef enum {
     ZSTD_defaultDisallowed = 0,
diff --git a/lib/compress/zstd_compress_superblock.c b/lib/compress/zstd_compress_superblock.c
index e44a14b62..b693866c0 100644
--- a/lib/compress/zstd_compress_superblock.c
+++ b/lib/compress/zstd_compress_superblock.c
@@ -11,12 +11,13 @@
  /*-*************************************
  *  Dependencies
  ***************************************/
-#include "hist.h"           /* HIST_countFast_wksp */
+#include "zstd_compress_superblock.h"
+
+#include "../common/zstd_internal.h"  /* ZSTD_getSequenceLength */
+#include "hist.h"                     /* HIST_countFast_wksp */
 #include "zstd_compress_internal.h"
 #include "zstd_compress_sequences.h"
 #include "zstd_compress_literals.h"
-#include "zstd_compress_superblock.h"
-#include "zstd_internal.h"  /* ZSTD_getSequenceLength */
 
 /*-*************************************
 *  Superblock entropy buffer structs
diff --git a/lib/compress/zstd_compress_superblock.h b/lib/compress/zstd_compress_superblock.h
index 35d207299..07f4cb1dc 100644
--- a/lib/compress/zstd_compress_superblock.h
+++ b/lib/compress/zstd_compress_superblock.h
@@ -15,7 +15,7 @@
 *  Dependencies
 ***************************************/
 
-#include "zstd.h" /* ZSTD_CCtx */
+#include "../zstd.h" /* ZSTD_CCtx */
 
 /*-*************************************
 *  Target Compressed Block Size
diff --git a/lib/compress/zstd_cwksp.h b/lib/compress/zstd_cwksp.h
index 91f812fa3..a25c9263b 100644
--- a/lib/compress/zstd_cwksp.h
+++ b/lib/compress/zstd_cwksp.h
@@ -14,7 +14,7 @@
 /*-*************************************
 *  Dependencies
 ***************************************/
-#include "zstd_internal.h"
+#include "../common/zstd_internal.h"
 
 #if defined (__cplusplus)
 extern "C" {
diff --git a/lib/compress/zstd_double_fast.h b/lib/compress/zstd_double_fast.h
index 73a2002f3..14d944d69 100644
--- a/lib/compress/zstd_double_fast.h
+++ b/lib/compress/zstd_double_fast.h
@@ -15,7 +15,7 @@
 extern "C" {
 #endif
 
-#include "mem.h"      /* U32 */
+#include "../common/mem.h"      /* U32 */
 #include "zstd_compress_internal.h"     /* ZSTD_CCtx, size_t */
 
 void ZSTD_fillDoubleHashTable(ZSTD_matchState_t* ms,
diff --git a/lib/compress/zstd_fast.h b/lib/compress/zstd_fast.h
index 3e15cc85c..cf6aaa8e6 100644
--- a/lib/compress/zstd_fast.h
+++ b/lib/compress/zstd_fast.h
@@ -15,7 +15,7 @@
 extern "C" {
 #endif
 
-#include "mem.h"      /* U32 */
+#include "../common/mem.h"      /* U32 */
 #include "zstd_compress_internal.h"
 
 void ZSTD_fillHashTable(ZSTD_matchState_t* ms,
diff --git a/lib/compress/zstd_ldm.c b/lib/compress/zstd_ldm.c
index 0e72c0b59..2a1c2cd62 100644
--- a/lib/compress/zstd_ldm.c
+++ b/lib/compress/zstd_ldm.c
@@ -10,7 +10,7 @@
 
 #include "zstd_ldm.h"
 
-#include "debug.h"
+#include "../common/debug.h"
 #include "zstd_fast.h"          /* ZSTD_fillHashTable() */
 #include "zstd_double_fast.h"   /* ZSTD_fillDoubleHashTable() */
 
diff --git a/lib/compress/zstd_ldm.h b/lib/compress/zstd_ldm.h
index aa2b6c52e..229ea05a9 100644
--- a/lib/compress/zstd_ldm.h
+++ b/lib/compress/zstd_ldm.h
@@ -16,7 +16,7 @@ extern "C" {
 #endif
 
 #include "zstd_compress_internal.h"   /* ldmParams_t, U32 */
-#include "zstd.h"   /* ZSTD_CCtx, size_t */
+#include "../zstd.h"   /* ZSTD_CCtx, size_t */
 
 /*-*************************************
 *  Long distance matching
diff --git a/lib/compress/zstdmt_compress.c b/lib/compress/zstdmt_compress.c
index 56186f506..f6b26a757 100644
--- a/lib/compress/zstdmt_compress.c
+++ b/lib/compress/zstdmt_compress.c
@@ -22,9 +22,9 @@
 /* ======   Dependencies   ====== */
 #include <string.h>      /* memcpy, memset */
 #include <limits.h>      /* INT_MAX, UINT_MAX */
-#include "mem.h"         /* MEM_STATIC */
-#include "pool.h"        /* threadpool */
-#include "threading.h"   /* mutex */
+#include "../common/mem.h"         /* MEM_STATIC */
+#include "../common/pool.h"        /* threadpool */
+#include "../common/threading.h"   /* mutex */
 #include "zstd_compress_internal.h"  /* MIN, ERROR, ZSTD_*, ZSTD_highbit32 */
 #include "zstd_ldm.h"
 #include "zstdmt_compress.h"
diff --git a/lib/compress/zstdmt_compress.h b/lib/compress/zstdmt_compress.h
index b90fd389a..89914eb7f 100644
--- a/lib/compress/zstdmt_compress.h
+++ b/lib/compress/zstdmt_compress.h
@@ -40,7 +40,7 @@
 /* ===   Dependencies   === */
 #include <stddef.h>                /* size_t */
 #define ZSTD_STATIC_LINKING_ONLY   /* ZSTD_parameters */
-#include "zstd.h"            /* ZSTD_inBuffer, ZSTD_outBuffer, ZSTDLIB_API */
+#include "../zstd.h"            /* ZSTD_inBuffer, ZSTD_outBuffer, ZSTDLIB_API */
 
 
 /* ===   Constants   === */
diff --git a/lib/decompress/huf_decompress.c b/lib/decompress/huf_decompress.c
index ab5db481c..68293a130 100644
--- a/lib/decompress/huf_decompress.c
+++ b/lib/decompress/huf_decompress.c
@@ -16,12 +16,12 @@
 *  Dependencies
 ****************************************************************/
 #include <string.h>     /* memcpy, memset */
-#include "compiler.h"
-#include "bitstream.h"  /* BIT_* */
-#include "fse.h"        /* to compress headers */
+#include "../common/compiler.h"
+#include "../common/bitstream.h"  /* BIT_* */
+#include "../common/fse.h"        /* to compress headers */
 #define HUF_STATIC_LINKING_ONLY
-#include "huf.h"
-#include "error_private.h"
+#include "../common/huf.h"
+#include "../common/error_private.h"
 
 /* **************************************************************
 *  Macros
diff --git a/lib/decompress/zstd_ddict.c b/lib/decompress/zstd_ddict.c
index 70477ca7d..042a7bc85 100644
--- a/lib/decompress/zstd_ddict.c
+++ b/lib/decompress/zstd_ddict.c
@@ -15,17 +15,17 @@
 *  Dependencies
 *********************************************************/
 #include <string.h>      /* memcpy, memmove, memset */
-#include "cpu.h"         /* bmi2 */
-#include "mem.h"         /* low level memory routines */
+#include "../common/cpu.h"         /* bmi2 */
+#include "../common/mem.h"         /* low level memory routines */
 #define FSE_STATIC_LINKING_ONLY
-#include "fse.h"
+#include "../common/fse.h"
 #define HUF_STATIC_LINKING_ONLY
-#include "huf.h"
+#include "../common/huf.h"
 #include "zstd_decompress_internal.h"
 #include "zstd_ddict.h"
 
 #if defined(ZSTD_LEGACY_SUPPORT) && (ZSTD_LEGACY_SUPPORT>=1)
-#  include "zstd_legacy.h"
+#  include "../legacy/zstd_legacy.h"
 #endif
 
 
diff --git a/lib/decompress/zstd_ddict.h b/lib/decompress/zstd_ddict.h
index 3ab7532ee..af307efd3 100644
--- a/lib/decompress/zstd_ddict.h
+++ b/lib/decompress/zstd_ddict.h
@@ -16,7 +16,7 @@
  *  Dependencies
  *********************************************************/
 #include <stddef.h>   /* size_t */
-#include "zstd.h"     /* ZSTD_DDict, and several public functions */
+#include "../zstd.h"     /* ZSTD_DDict, and several public functions */
 
 
 /*-*******************************************************
diff --git a/lib/decompress/zstd_decompress.c b/lib/decompress/zstd_decompress.c
index 91adb8a6e..90ddeaabe 100644
--- a/lib/decompress/zstd_decompress.c
+++ b/lib/decompress/zstd_decompress.c
@@ -56,19 +56,19 @@
 *  Dependencies
 *********************************************************/
 #include <string.h>      /* memcpy, memmove, memset */
-#include "cpu.h"         /* bmi2 */
-#include "mem.h"         /* low level memory routines */
+#include "../common/cpu.h"         /* bmi2 */
+#include "../common/mem.h"         /* low level memory routines */
 #define FSE_STATIC_LINKING_ONLY
-#include "fse.h"
+#include "../common/fse.h"
 #define HUF_STATIC_LINKING_ONLY
-#include "huf.h"
-#include "zstd_internal.h"  /* blockProperties_t */
+#include "../common/huf.h"
+#include "../common/zstd_internal.h"  /* blockProperties_t */
 #include "zstd_decompress_internal.h"   /* ZSTD_DCtx */
 #include "zstd_ddict.h"  /* ZSTD_DDictDictContent */
 #include "zstd_decompress_block.h"   /* ZSTD_decompressBlock_internal */
 
 #if defined(ZSTD_LEGACY_SUPPORT) && (ZSTD_LEGACY_SUPPORT>=1)
-#  include "zstd_legacy.h"
+#  include "../legacy/zstd_legacy.h"
 #endif
 
 
diff --git a/lib/decompress/zstd_decompress_block.c b/lib/decompress/zstd_decompress_block.c
index 5a1226eba..6eb7462cd 100644
--- a/lib/decompress/zstd_decompress_block.c
+++ b/lib/decompress/zstd_decompress_block.c
@@ -15,14 +15,14 @@
 *  Dependencies
 *********************************************************/
 #include <string.h>      /* memcpy, memmove, memset */
-#include "compiler.h"    /* prefetch */
-#include "cpu.h"         /* bmi2 */
-#include "mem.h"         /* low level memory routines */
+#include "../common/compiler.h"    /* prefetch */
+#include "../common/cpu.h"         /* bmi2 */
+#include "../common/mem.h"         /* low level memory routines */
 #define FSE_STATIC_LINKING_ONLY
-#include "fse.h"
+#include "../common/fse.h"
 #define HUF_STATIC_LINKING_ONLY
-#include "huf.h"
-#include "zstd_internal.h"
+#include "../common/huf.h"
+#include "../common/zstd_internal.h"
 #include "zstd_decompress_internal.h"   /* ZSTD_DCtx */
 #include "zstd_ddict.h"  /* ZSTD_DDictDictContent */
 #include "zstd_decompress_block.h"
diff --git a/lib/decompress/zstd_decompress_block.h b/lib/decompress/zstd_decompress_block.h
index a065f8d93..bf39b7350 100644
--- a/lib/decompress/zstd_decompress_block.h
+++ b/lib/decompress/zstd_decompress_block.h
@@ -16,8 +16,8 @@
  *  Dependencies
  *********************************************************/
 #include <stddef.h>   /* size_t */
-#include "zstd.h"    /* DCtx, and some public functions */
-#include "zstd_internal.h"  /* blockProperties_t, and some public functions */
+#include "../zstd.h"    /* DCtx, and some public functions */
+#include "../common/zstd_internal.h"  /* blockProperties_t, and some public functions */
 #include "zstd_decompress_internal.h"  /* ZSTD_seqSymbol */
 
 
diff --git a/lib/decompress/zstd_decompress_internal.h b/lib/decompress/zstd_decompress_internal.h
index f1c2585a6..8c4f79f46 100644
--- a/lib/decompress/zstd_decompress_internal.h
+++ b/lib/decompress/zstd_decompress_internal.h
@@ -19,8 +19,8 @@
 /*-*******************************************************
  *  Dependencies
  *********************************************************/
-#include "mem.h"             /* BYTE, U16, U32 */
-#include "zstd_internal.h"   /* ZSTD_seqSymbol */
+#include "../common/mem.h"             /* BYTE, U16, U32 */
+#include "../common/zstd_internal.h"   /* ZSTD_seqSymbol */
 
 
 
diff --git a/lib/deprecated/zbuff.h b/lib/deprecated/zbuff.h
index 7686f76a4..03cb14a03 100644
--- a/lib/deprecated/zbuff.h
+++ b/lib/deprecated/zbuff.h
@@ -28,7 +28,7 @@ extern "C" {
 *  Dependencies
 ***************************************/
 #include <stddef.h>      /* size_t */
-#include "zstd.h"        /* ZSTD_CStream, ZSTD_DStream, ZSTDLIB_API */
+#include "../zstd.h"        /* ZSTD_CStream, ZSTD_DStream, ZSTDLIB_API */
 
 
 /* ***************************************************************
@@ -186,7 +186,7 @@ ZBUFF_DEPRECATED("use ZSTD_DStreamOutSize") size_t ZBUFF_recommendedDOutSize(voi
 
 /*--- Dependency ---*/
 #define ZSTD_STATIC_LINKING_ONLY   /* ZSTD_parameters, ZSTD_customMem */
-#include "zstd.h"
+#include "../zstd.h"
 
 
 /*--- Custom memory allocator ---*/
diff --git a/lib/deprecated/zbuff_common.c b/lib/deprecated/zbuff_common.c
index e2b9613f0..579bc4df1 100644
--- a/lib/deprecated/zbuff_common.c
+++ b/lib/deprecated/zbuff_common.c
@@ -11,7 +11,7 @@
 /*-*************************************
 *  Dependencies
 ***************************************/
-#include "error_private.h"
+#include "../common/error_private.h"
 #include "zbuff.h"
 
 /*-****************************************
diff --git a/lib/dictBuilder/cover.c b/lib/dictBuilder/cover.c
index b57981c52..da54ef15f 100644
--- a/lib/dictBuilder/cover.c
+++ b/lib/dictBuilder/cover.c
@@ -26,11 +26,11 @@
 #include <string.h> /* memset */
 #include <time.h>   /* clock */
 
-#include "mem.h" /* read */
-#include "pool.h"
-#include "threading.h"
+#include "../common/mem.h" /* read */
+#include "../common/pool.h"
+#include "../common/threading.h"
 #include "cover.h"
-#include "zstd_internal.h" /* includes zstd.h */
+#include "../common/zstd_internal.h" /* includes zstd.h */
 #ifndef ZDICT_STATIC_LINKING_ONLY
 #define ZDICT_STATIC_LINKING_ONLY
 #endif
diff --git a/lib/dictBuilder/cover.h b/lib/dictBuilder/cover.h
index 77943f0a7..f2aa0e35e 100644
--- a/lib/dictBuilder/cover.h
+++ b/lib/dictBuilder/cover.h
@@ -12,10 +12,10 @@
 #include <stdlib.h> /* malloc, free, qsort */
 #include <string.h> /* memset */
 #include <time.h>   /* clock */
-#include "mem.h" /* read */
-#include "pool.h"
-#include "threading.h"
-#include "zstd_internal.h" /* includes zstd.h */
+#include "../common/mem.h" /* read */
+#include "../common/pool.h"
+#include "../common/threading.h"
+#include "../common/zstd_internal.h" /* includes zstd.h */
 #ifndef ZDICT_STATIC_LINKING_ONLY
 #define ZDICT_STATIC_LINKING_ONLY
 #endif
diff --git a/lib/dictBuilder/fastcover.c b/lib/dictBuilder/fastcover.c
index 5bc9ca50f..485c333b5 100644
--- a/lib/dictBuilder/fastcover.c
+++ b/lib/dictBuilder/fastcover.c
@@ -16,11 +16,11 @@
 #include <string.h> /* memset */
 #include <time.h>   /* clock */
 
-#include "mem.h" /* read */
-#include "pool.h"
-#include "threading.h"
+#include "../common/mem.h" /* read */
+#include "../common/pool.h"
+#include "../common/threading.h"
 #include "cover.h"
-#include "zstd_internal.h" /* includes zstd.h */
+#include "../common/zstd_internal.h" /* includes zstd.h */
 #ifndef ZDICT_STATIC_LINKING_ONLY
 #define ZDICT_STATIC_LINKING_ONLY
 #endif
diff --git a/lib/dictBuilder/zdict.c b/lib/dictBuilder/zdict.c
index 6fa1ca699..6d0b04231 100644
--- a/lib/dictBuilder/zdict.c
+++ b/lib/dictBuilder/zdict.c
@@ -37,18 +37,18 @@
 #include <stdio.h>         /* fprintf, fopen, ftello64 */
 #include <time.h>          /* clock */
 
-#include "mem.h"           /* read */
-#include "fse.h"           /* FSE_normalizeCount, FSE_writeNCount */
+#include "../common/mem.h"           /* read */
+#include "../common/fse.h"           /* FSE_normalizeCount, FSE_writeNCount */
 #define HUF_STATIC_LINKING_ONLY
-#include "huf.h"           /* HUF_buildCTable, HUF_writeCTable */
-#include "zstd_internal.h" /* includes zstd.h */
-#include "xxhash.h"        /* XXH64 */
+#include "../common/huf.h"           /* HUF_buildCTable, HUF_writeCTable */
+#include "../common/zstd_internal.h" /* includes zstd.h */
+#include "../common/xxhash.h"        /* XXH64 */
 #include "divsufsort.h"
 #ifndef ZDICT_STATIC_LINKING_ONLY
 #  define ZDICT_STATIC_LINKING_ONLY
 #endif
 #include "zdict.h"
-#include "compress/zstd_compress_internal.h" /* ZSTD_loadCEntropy() */
+#include "../compress/zstd_compress_internal.h" /* ZSTD_loadCEntropy() */
 
 
 /*-*************************************
diff --git a/lib/legacy/zstd_legacy.h b/lib/legacy/zstd_legacy.h
index ecd968212..6bea6a519 100644
--- a/lib/legacy/zstd_legacy.h
+++ b/lib/legacy/zstd_legacy.h
@@ -18,9 +18,9 @@ extern "C" {
 /* *************************************
 *  Includes
 ***************************************/
-#include "mem.h"            /* MEM_STATIC */
-#include "error_private.h"  /* ERROR */
-#include "zstd_internal.h"  /* ZSTD_inBuffer, ZSTD_outBuffer, ZSTD_frameSizeInfo */
+#include "../common/mem.h"            /* MEM_STATIC */
+#include "../common/error_private.h"  /* ERROR */
+#include "../common/zstd_internal.h"  /* ZSTD_inBuffer, ZSTD_outBuffer, ZSTD_frameSizeInfo */
 
 #if !defined (ZSTD_LEGACY_SUPPORT) || (ZSTD_LEGACY_SUPPORT == 0)
 #  undef ZSTD_LEGACY_SUPPORT
diff --git a/lib/legacy/zstd_v01.c b/lib/legacy/zstd_v01.c
index 4d5ecf7d3..0517222ca 100644
--- a/lib/legacy/zstd_v01.c
+++ b/lib/legacy/zstd_v01.c
@@ -14,7 +14,7 @@
 ******************************************/
 #include <stddef.h>    /* size_t, ptrdiff_t */
 #include "zstd_v01.h"
-#include "error_private.h"
+#include "../common/error_private.h"
 
 
 /******************************************
diff --git a/lib/legacy/zstd_v02.c b/lib/legacy/zstd_v02.c
index 7105aa49a..a7aa27cdf 100644
--- a/lib/legacy/zstd_v02.c
+++ b/lib/legacy/zstd_v02.c
@@ -11,7 +11,7 @@
 
 #include <stddef.h>    /* size_t, ptrdiff_t */
 #include "zstd_v02.h"
-#include "error_private.h"
+#include "../common/error_private.h"
 
 
 /******************************************
diff --git a/lib/legacy/zstd_v03.c b/lib/legacy/zstd_v03.c
index 980cf02f1..1b00c98bf 100644
--- a/lib/legacy/zstd_v03.c
+++ b/lib/legacy/zstd_v03.c
@@ -11,7 +11,7 @@
 
 #include <stddef.h>    /* size_t, ptrdiff_t */
 #include "zstd_v03.h"
-#include "error_private.h"
+#include "../common/error_private.h"
 
 
 /******************************************
diff --git a/lib/legacy/zstd_v04.c b/lib/legacy/zstd_v04.c
index e5b51f782..1a3d49cf6 100644
--- a/lib/legacy/zstd_v04.c
+++ b/lib/legacy/zstd_v04.c
@@ -16,7 +16,7 @@
 #include <string.h>    /* memcpy */
 
 #include "zstd_v04.h"
-#include "error_private.h"
+#include "../common/error_private.h"
 
 
 /* ******************************************************************
diff --git a/lib/legacy/zstd_v05.c b/lib/legacy/zstd_v05.c
index 649144d04..79ea59a1b 100644
--- a/lib/legacy/zstd_v05.c
+++ b/lib/legacy/zstd_v05.c
@@ -11,7 +11,7 @@
 
 /*- Dependencies -*/
 #include "zstd_v05.h"
-#include "error_private.h"
+#include "../common/error_private.h"
 
 
 /* ******************************************************************
diff --git a/lib/legacy/zstd_v05.h b/lib/legacy/zstd_v05.h
index 6c46e8f23..167d892e6 100644
--- a/lib/legacy/zstd_v05.h
+++ b/lib/legacy/zstd_v05.h
@@ -19,7 +19,7 @@ extern "C" {
 *  Dependencies
 ***************************************/
 #include <stddef.h>   /* size_t */
-#include "mem.h"      /* U64, U32 */
+#include "../common/mem.h"      /* U64, U32 */
 
 
 /* *************************************
diff --git a/lib/legacy/zstd_v06.c b/lib/legacy/zstd_v06.c
index 288eebe81..1a670fad0 100644
--- a/lib/legacy/zstd_v06.c
+++ b/lib/legacy/zstd_v06.c
@@ -14,7 +14,7 @@
 #include <stddef.h>    /* size_t, ptrdiff_t */
 #include <string.h>    /* memcpy */
 #include <stdlib.h>    /* malloc, free, qsort */
-#include "error_private.h"
+#include "../common/error_private.h"
 
 
 
diff --git a/lib/legacy/zstd_v07.c b/lib/legacy/zstd_v07.c
index 36593d38b..5393475da 100644
--- a/lib/legacy/zstd_v07.c
+++ b/lib/legacy/zstd_v07.c
@@ -17,14 +17,14 @@
 #ifndef XXH_STATIC_LINKING_ONLY
 #  define XXH_STATIC_LINKING_ONLY    /* XXH64_state_t */
 #endif
-#include "xxhash.h"                  /* XXH64_* */
+#include "../common/xxhash.h"                  /* XXH64_* */
 #include "zstd_v07.h"
 
 #define FSEv07_STATIC_LINKING_ONLY   /* FSEv07_MIN_TABLELOG */
 #define HUFv07_STATIC_LINKING_ONLY   /* HUFv07_TABLELOG_ABSOLUTEMAX */
 #define ZSTDv07_STATIC_LINKING_ONLY
 
-#include "error_private.h"
+#include "../common/error_private.h"
 
 
 #ifdef ZSTDv07_STATIC_LINKING_ONLY
diff --git a/programs/Makefile b/programs/Makefile
index abad6da6b..1a85f185e 100644
--- a/programs/Makefile
+++ b/programs/Makefile
@@ -43,9 +43,7 @@ else
 ALIGN_LOOP =
 endif
 
-CPPFLAGS+= -I$(ZSTDDIR) -I$(ZSTDDIR)/common -I$(ZSTDDIR)/compress \
-           -I$(ZSTDDIR)/dictBuilder \
-           -DXXH_NAMESPACE=ZSTD_
+CPPFLAGS+= -DXXH_NAMESPACE=ZSTD_
 ifeq ($(OS),Windows_NT)   # MinGW assumed
 CPPFLAGS   += -D__USE_MINGW_ANSI_STDIO   # compatibility with %zu formatting
 endif
@@ -72,7 +70,6 @@ ifneq ($(ZSTD_LEGACY_SUPPORT), 0)
 ifeq ($(shell test $(ZSTD_LEGACY_SUPPORT) -lt 8; echo $$?), 0)
 	ZSTDLEGACY_FILES += $(shell ls $(ZSTDDIR)/legacy/*.c | $(GREP) 'v0[$(ZSTD_LEGACY_SUPPORT)-7]')
 endif
-	CPPFLAGS += -I$(ZSTDDIR)/legacy
 else
 endif
 
diff --git a/programs/benchzstd.c b/programs/benchzstd.c
index 80e98050c..77056203d 100644
--- a/programs/benchzstd.c
+++ b/programs/benchzstd.c
@@ -30,13 +30,13 @@
 
 #include "timefn.h"      /* UTIL_time_t */
 #include "benchfn.h"
-#include "mem.h"
+#include "../lib/common/mem.h"
 #define ZSTD_STATIC_LINKING_ONLY
-#include "zstd.h"
+#include "../lib/zstd.h"
 #include "datagen.h"     /* RDG_genBuffer */
-#include "xxhash.h"
+#include "../lib/common/xxhash.h"
 #include "benchzstd.h"
-#include "zstd_errors.h"
+#include "../lib/common/zstd_errors.h"
 
 
 /* *************************************
diff --git a/programs/benchzstd.h b/programs/benchzstd.h
index 99fae56a0..8c55b3c4f 100644
--- a/programs/benchzstd.h
+++ b/programs/benchzstd.h
@@ -24,7 +24,7 @@ extern "C" {
 /* ===  Dependencies  === */
 #include <stddef.h>   /* size_t */
 #define ZSTD_STATIC_LINKING_ONLY   /* ZSTD_compressionParameters */
-#include "zstd.h"     /* ZSTD_compressionParameters */
+#include "../lib/zstd.h"     /* ZSTD_compressionParameters */
 
 
 /* ===  Constants  === */
diff --git a/programs/datagen.c b/programs/datagen.c
index 7cf83bdaa..4353b7ff9 100644
--- a/programs/datagen.c
+++ b/programs/datagen.c
@@ -18,7 +18,7 @@
 #include <stdlib.h>    /* malloc, free */
 #include <stdio.h>     /* FILE, fwrite, fprintf */
 #include <string.h>    /* memcpy */
-#include "mem.h"       /* U32 */
+#include "../lib/common/mem.h"  /* U32 */
 
 
 /*-************************************
diff --git a/programs/dibio.c b/programs/dibio.c
index 2b322b639..463095a8e 100644
--- a/programs/dibio.c
+++ b/programs/dibio.c
@@ -30,8 +30,8 @@
 #include <assert.h>
 
 #include "timefn.h"         /* UTIL_time_t, UTIL_clockSpanMicro, UTIL_getTime */
-#include "mem.h"            /* read */
-#include "error_private.h"
+#include "../lib/common/mem.h"  /* read */
+#include "../lib/common/error_private.h"
 #include "dibio.h"
 
 
diff --git a/programs/dibio.h b/programs/dibio.h
index 436bddbb5..682723d6a 100644
--- a/programs/dibio.h
+++ b/programs/dibio.h
@@ -19,7 +19,7 @@
 *  Dependencies
 ***************************************/
 #define ZDICT_STATIC_LINKING_ONLY
-#include "zdict.h"     /* ZDICT_params_t */
+#include "../lib/dictBuilder/zdict.h"     /* ZDICT_params_t */
 
 
 /*-*************************************
diff --git a/programs/fileio.c b/programs/fileio.c
index 802e6fb61..d72879d64 100644
--- a/programs/fileio.c
+++ b/programs/fileio.c
@@ -39,13 +39,13 @@
 #  include <io.h>
 #endif
 
-#include "mem.h"       /* U32, U64 */
+#include "../lib/common/mem.h"     /* U32, U64 */
 #include "fileio.h"
 
 #define ZSTD_STATIC_LINKING_ONLY   /* ZSTD_magicNumber, ZSTD_frameHeaderSize_max */
-#include "zstd.h"
-#include "zstd_errors.h"           /* ZSTD_error_frameParameter_windowTooLarge */
-#include "zstd_compress_internal.h"
+#include "../lib/zstd.h"
+#include "../lib/common/zstd_errors.h"  /* ZSTD_error_frameParameter_windowTooLarge */
+#include "../lib/compress/zstd_compress_internal.h"
 
 #if defined(ZSTD_GZCOMPRESS) || defined(ZSTD_GZDECOMPRESS)
 #  include <zlib.h>
diff --git a/programs/fileio.h b/programs/fileio.h
index 565cbae11..2fbf01f82 100644
--- a/programs/fileio.h
+++ b/programs/fileio.h
@@ -13,7 +13,7 @@
 #define FILEIO_H_23981798732
 
 #define ZSTD_STATIC_LINKING_ONLY   /* ZSTD_compressionParameters */
-#include "zstd.h"                  /* ZSTD_* */
+#include "../lib/zstd.h"           /* ZSTD_* */
 
 #if defined (__cplusplus)
 extern "C" {
diff --git a/programs/util.h b/programs/util.h
index 40200729a..8e187e4f2 100644
--- a/programs/util.h
+++ b/programs/util.h
@@ -23,7 +23,7 @@ extern "C" {
 #include <stddef.h>       /* size_t, ptrdiff_t */
 #include <sys/types.h>    /* stat, utime */
 #include <sys/stat.h>     /* stat, chmod */
-#include "mem.h"          /* U64 */
+#include "../lib/common/mem.h"          /* U64 */
 
 
 /*-************************************************************
diff --git a/programs/zstdcli.c b/programs/zstdcli.c
index 3e293c57b..81f1910c2 100644
--- a/programs/zstdcli.c
+++ b/programs/zstdcli.c
@@ -40,7 +40,7 @@
 #ifndef ZSTD_NODICT
 #  include "dibio.h"  /* ZDICT_cover_params_t, DiB_trainFromFiles() */
 #endif
-#include "zstd.h"     /* ZSTD_VERSION_STRING, ZSTD_minCLevel, ZSTD_maxCLevel */
+#include "../lib/zstd.h"  /* ZSTD_VERSION_STRING, ZSTD_minCLevel, ZSTD_maxCLevel */
 
 
 /*-************************************