The JCC Basic standard library - a part of JCC.
The standard library is not usable on its own. It is distributed with JCC as jccbasic.dll.
To build the JCC Basic standard library, you need the 64-bit version of MinGW, as well as some tools that are not normally part of Windows.
The 64-bit version of MinGW can be downloaded from their home page mingw-w64 or as pre-built binaries from MinGW-W64-binaries.
GNU make for Windows can be downloaded from the GnuWin32 project.
The makefile uses the *nix tools mkdir and rm. These can also be downloaded from the GnuWin32 project as part of the CoreUtils package.
An alternative is to install bash, for example as part of Git.