To use that library in your C/C++ project, you just need to copy one file from this directory, or otherwise integrate that one file into your build system. Typically, pick the latest stable version (but not the unsupported snapshot), with a filename like
wuffs-vMAJOR.MINOR.c for version MAJOR.MINOR.
To use that single file as a “foo.c”-like implementation, instead of a “foo.h”-like header,
#define WUFFS_IMPLEMENTATION before
#include'ing or compiling it.
Version 0.2 (December 2019) is the latest stable version. Stable means that its API won't change any further, but being a “version 0.x” means that: