The compiler by itself attempts to be what the ISO/ANSI C standard calls a conforming freestanding implementation. This means all ANSI C language features are available, as well as the contents of float.h, limits.h, stdarg.h, and stddef.h.
The compilation system includes the XGC Libraries, that offer most of the functions from the ANSI C Libraries libc and libm, and a subset of POSIX Threads that is compatible with Solaris 2.5 Threads.