ifdef cleanup
Get rid of a lot of unnecessary ifdefs that just make the code harder to understand and aren't used on the platforms we support today.
- unifdef
__osf__
- unifdef
AIXV3
- unifdef
ultrix
- unifdef
__UNIXOS2__
- unifdef
hpux
- unifdef
sgi
- unifdef
__sgi
- unifdef
__sgi_not_xconsortium
- unifdef
__vax__
- unifdef
__uxp__
- unifdef
__QNX__