Single-file decoder script can now (optionally) create an encoder

To complement the single-file decoder a new script was added to create an amalgamated single-file of all of the Zstd source, along with examples and (simple) tests.

contrib/single_file_decoder/build_decoder_test.sh

@@ -0,0 +1,55 @@
+#!/bin/sh
+
+# Temporary compiled binary
+OUT_FILE="tempbin"
+
+# Optional temporary compiled WebAssembly
+OUT_WASM="temp.wasm"
+
+# Amalgamate the sources
+./create_single_file_decoder.sh
+# Did combining work?
+if [ $? -ne 0 ]; then
+  echo "Single file decoder creation script: FAILED"
+  exit 1
+fi
+echo "Single file decoder creation script: PASSED"
+
+# Compile the generated output
+cc -Wall -Wextra -Werror -Os -g0 -o $OUT_FILE examples/simple.c
+# Did compilation work?
+if [ $? -ne 0 ]; then
+  echo "Compiling simple.c: FAILED"
+  exit 1
+fi
+echo "Compiling simple.c: PASSED"
+
+# Run then delete the compiled output
+./$OUT_FILE
+retVal=$?
+rm -f $OUT_FILE
+# Did the test work?
+if [ $retVal -ne 0 ]; then
+  echo "Running simple.c: FAILED"
+  exit 1
+fi
+echo "Running simple.c: PASSED"
+
+# Is Emscripten available?
+which emcc > /dev/null
+if [ $? -ne 0 ]; then
+  echo "(Skipping Emscripten test)"
+else
+  # Compile the Emscripten example
+  CC_FLAGS="-Wall -Wextra -Werror -Os -g0 -flto --llvm-lto 3 -lGL -DNDEBUG=1"
+  emcc $CC_FLAGS -s WASM=1 -o $OUT_WASM examples/emscripten.c
+  # Did compilation work?
+  if [ $? -ne 0 ]; then
+    echo "Compiling emscripten.c: FAILED"
+    exit 1
+  fi
+  echo "Compiling emscripten.c: PASSED"
+  rm -f $OUT_WASM
+fi
+
+exit 0