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/create_single_file_library.sh

@@ -0,0 +1,14 @@
+#!/bin/sh
+
+# Where to find the sources
+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
+# Did combining work?
+if [ $? -ne 0 ]; then
+  echo "Combine script: FAILED"
+  exit 1
+fi
+echo "Combine script: PASSED"