aix                  for AIX 4.x with xlC
aix5                 for AIX 5.x with xlC
aixgcc               for AIX 5.x with gcc >= 3
alphacxx6            for DEC Unix with cxx6
alphagcc             for DEC Unix with gcc
alphakcc             for DEC Unix with KCC
freebsd4             for FreeBSD 4.x with gcc
freebsd5             for FreeBSD 5.x and 6.x with gcc
freebsd7             for FreeBSD 7.x with gcc
hpuxacc              for HP-UX 10.20 with HP aCC
hpuxgcc              for HP-UX 10.20 with gcc
hpuxia64acc          for HP-UX 11i v1.5 (IA-64) with HP aCC
hurddeb              for Debian GNU/Hurd with gcc
linux                for i386 Linux with gcc >= 3
linuxicc             for i386 Linux with Intel's icc
linuxkcc             for i386 Linux with KAI's KCC
linuxpgcc            for i386 Linux with pgcc
linuxalphagcc        for Alpha Linux with gcc
linuxarm             for ARM Linux with gcc
linuxdeb2ppc         for PPC Linux based on Debian v2.0 with gcc
linuxhppa            for HPPA Linux with gcc
linuxia64ecc         for Itanium Linux with Intel icc
linuxia64gcc         for Itanium Linux with gcc >= 3
linuxia64sgi         for Itanium Linux with sgiCC
linuxmips            for MIPS Linux with gcc
linuxppcgcc          for PPC Linux with gcc
linuxppc64gcc        for PPC 64 Linux  with gcc >= 3
linuxx8664gcc        for x86-64 Linux with gcc >= 3.x
linuxx8664icc        for x86-64 Linux with Intel icc >=10.x
lynxos               for LynxOS with gcc
macosx               for MacOS X >= 10.4 with gcc
macosxicc            for MacOS X >= 10.4 with Intel icc (Intel only)
macosx64             for MacOS X >= 10.5 with gcc 4.0 64 bit mode
macosxxlc            for MacOS X >= 10.4 with IBM xl compilers (PPC only)
openbsd              for OpenBSD >= 3.7 with gcc
sgicc                for SGI IRIX 6.x with CC
sgicc64              for SGI IRIX 6.x with CC 64 bits
sgigcc               for SGI IRIX 6.x with gcc
sgikcc               for SGI IRIX 6.x with KCC
sgin32gcc            for SGI IRIX 6.4 with gcc using n32 ABI
solaris              for Solaris with CC
solarisCC5           for Solaris with CC 5.0
solarisgcc           for Solaris with gcc
solariskcc           for Solaris with KCC
win32                for Win32 with VC++ and gdk based GUI
win32gcc             for Win32 with cygwin/gcc