Win32 miniperl: delay loading for Winsock, and then remove it

Win32 miniperl: delay loading for Winsock, and then remove it

Slim down the image and speed up start up time for Win32 miniperl by
removing Winsock. Also if the build process on Win32 in the future
requires sockets, commenting one line in win32.h will turn sockets back on
for miniperl, but this time with delay loading on VC Perl. The only casulty
of no sockets for Win32 miniperl was figuring out the computer's name in
win32/config_sh.PL. A workaround by using an ENV var was implemented. The
purpose of this commit is to speed up the build process of Perl.

As said in the comment in win32.h, the WIN32_NO_SOCKETS macro is
incomplete in implementation. It is only removed winsock from being linked
in in miniperl, not full Perl. PERL_IMPLICIT_SYS (specifically PerlSock in
win32/perlhost.h) and makedef.pl's hard coded list of win32_* function
exports cause winsock to still be linked in with even with
WIN32_NO_SOCKETS on full perl. Both PERL_IMPLICIT_SYS (win32/perlhost.h)
and makedef.pl would require changes to remove winsock from being linked
in on full perl in the future.