Hera are the flags you have to set in your C compiler in order to compile Pliant:

_LINUX_API_ _POSIX_API_ _WIN32_API_ _OS2_API_	Specify the API Pliant should use to deal with the operating system.
_i386_	Tells pliant what processor instructions set to use.
_GCC_ _WATCOM_ _MSVC_	Specify the compiler specific code to use.
_EXE_ _DLL_	_EXE_ means: compile Pliant as a standard executable using the C compiler bootstart code. _DLL_ means: compile Pliant as a DLL and a tiny loader.
c_debugging_level=x	Sets the debugging level in the C part of Pliant (0 to 2)
_CHECK_	Enables pliant debug check macros. Should be defined when debugging level is 2.