__CYGWIN__ Ditto
GNU_LINUX
HPUX
-IRIX6_5
MSDOS Compiling the MS-DOS port.
__MSDOS__ Ditto.
__DJGPP_MINOR__ Minor version number of the DJGPP library; used only in msdos.c and dosfns.c.
NSIG_MINIMUM
NULL_DEVICE
PAGESIZE
-PREFER_VSUSP
PTY_ITERATION
PTY_NAME_SPRINTF
PTY_OPEN