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
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
ios                  for Apple iOS on armv7 device
iossim               for Apple iOS on i386 simulator
linux                for i386 Linux with gcc >= 3
linuxicc             for i386 Linux with Intel's icc
linuxalphagcc        for Alpha Linux with gcc
linuxarm             for ARM Linux with gcc
linuxhppa            for HPPA Linux with gcc
linuxia64ecc         for Itanium Linux with Intel icc
linuxia64gcc         for Itanium Linux with gcc >= 3
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
linuxx8664k1omicc    for x86-64 Intel Many Integrated Cores Linux with Intel icc >=13.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
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
sgin32gcc            for SGI IRIX 6.4 with gcc using n32 ABI
solaris              for Solaris with CC
solarisCC5           for Solaris with CC 5.0
solaris64CC5         for Solaris with CC 5.0 64 bits
win32                for Win32 with VC++ and gdk based GUI
win32gcc             for Win32 with cygwin/gcc
win64gcc             for Win64 with cygwin/gcc