Get rid of HPuUX, use __hpux
Get rid of LINUX, use __linux__
Get rid of DARWIN, use __APPLE__
Replace custom MINGW with built-in __MINGW32__ macro
Get rid of hpux and __hpux__, use __hpux
Get rid of SOLARIS, use __sun instead
Get rid of AIX, use built-in _AIX instead
Remove {FREE,OPEN,NET}BSD, use built-in __{Free,Open,Net}BSD__ instead
Remove obsolete SUNOS macro
Remove SCO, UNIXWARE, CFCRAY macro, use built-in sco, __SCO_DS, _CRAY instead
Remove unused CFQNX, CFGNU macros
Get rid of NT macro, use built-in _WIN32 instead
Get rid of CFCYG macro, use built-in __CYGWIN__ instead
Simplify macro expressions involving __CYGWIN__
Whitespace