Make makedef.pl read "miniperl -V" on Win32

Make makedef.pl read "miniperl -V" on Win32

Perhaps other platforms that use makedef.pl also need a similar
change (currently required to pick up PERL_DONT_CREATE_GVSV),
but it also requires them to have minimal canned configs (if they
are using canned configs like Win32 does) and I don't have any
of the affected platforms (AIX, WinCE, OS/2, MacOS Classic and
NetWare) for testing, so play it safe instead

p4raw-id: //depot/perl@25209