CMake/Modules/CMakeCCompilerId.c

#ifdef __cplusplus
# error "A C++ compiler has been selected for C."
#endif

#ifdef __CLASSIC_C__
# define const
#endif

#if defined(__INTEL_COMPILER) || defined(__ICC)
# define COMPILER_ID "Intel"

#elif defined(__BORLANDC__)
# define COMPILER_ID "Borland"

#elif defined(__WATCOMC__)
# define COMPILER_ID "Watcom"

#elif defined(__SUNPRO_C)
# define COMPILER_ID "SunPro"

#elif defined(__HP_cc)
# define COMPILER_ID "HP"

#elif defined(__DECC)
# define COMPILER_ID "Compaq"

#elif defined(__IBMC__)
# define COMPILER_ID "VisualAge"

#elif defined(__GNUC__)
# define COMPILER_ID "GNU"

#elif defined(_MSC_VER)
# define COMPILER_ID "MSVC"

/* IAR Systems compiler for embedded systems.
   http://www.iar.com
   Beside this id not supported yet by CMake */
#elif defined(__IAR_SYSTEMS_ICC__)
# define COMPILER_ID "IAR"

/* sdcc, the small devices C compiler for embedded systems, 
   http://sdcc.sourceforge.net 
   Beside this id not supported yet by CMake 
   Unfortunately this doesn't work because SDCC (and other embedded compilers 
   too) produce not binary files, but e.g. Intel hex files by default. 
   This also means it has a different suffix (.ihx) so the file isn't even
   found. */
/*
#elif defined(SDCC)
# define COMPILER_ID "SDCC" */

#elif defined(_COMPILER_VERSION)
# define COMPILER_ID "MIPSpro"

/* This compiler is either not known or is too old to define an
   identification macro.  Try to identify the platform and guess that
   it is the native compiler.  */
#elif defined(__sgi)
# define COMPILER_ID "MIPSpro"

#elif defined(__hpux) || defined(__hpua)
# define COMPILER_ID "HP"

#else /* unknown compiler */
# define COMPILER_ID ""

#endif

static char const info_compiler[] = "INFO:compiler[" COMPILER_ID "]";

/* Include the platform identification source.  */
#include "CMakePlatformId.h"

/* Make sure the information strings are referenced.  */
int main()
{
  return (&info_compiler[0] != &info_platform[0]);
}