The test script combines the sources then builds and runs an example. A futher example is built if the Emscripten compiler is available on the system. Documentation covers building.
Single File Zstandard Decompression Library
The script combine.sh creates an amalgamted source file that can be used with out without zstd.h. This isn't a header-only file but it does offer a similar level of simplicity when integrating into a project.
Create zstddeclib.c from the Zstd source using:
cd zstd/contrib/declib
./combine.sh -r ../../lib -r ../../lib/common -r ../../lib/decompress -o zstddeclib.c zstddeclib-in.c
Then add the resulting file to your project (see the example files).
build.sh will run the above script then compile and test the resulting library.