Operating Systems:
-----------------
SunOS .. 4.1:		sun		(abbr.: SunOS4)
Solaris:		sun __svr4__	(abbr.: solaris)
Silicon Graphics:	sgi
Atari ST/TT MiNT:	atarist
Amiga, DICE:		AMIGA _DCC
Amiga, SAS/C:		AMIGA __SASC
Linux:			linux
NeXT:			NeXT
Sequent:		_SEQUENT_
Ultrix:			ultrix
IBM RS6000		_AIX _IBMR2
HP-UX			hpux
OS/2			OS2 (not always set by the compiler???)
???			M_UNIX

Program Loaders:
---------------
msdos:			MSDOS

Processor Hardware:
------------------
Sparc			sparc

compilers:
---------
gcc:			__GNUC__