temporarily[!] removes support for couple of esoteric platforms [well,
Netware, vxWorks and VMS].

all Windows targets.

handles properly by bss_file.c, which renders _fmode redundant.

to open/read/write/close. First OPENSSL_NO_POSIX_IO target would be
Windows CE.

all _WIN32 [see commentary for clarification].

[as per http://cvs.openssl.org/chngview?cn=14551].

PR: 1218

(This were in 0.9.7-stable and 0.9.8-stable, but not in HEAD so far.)

PR: 1218,1185

loop option, which can give further 3KB code reduction.