unifdef.c: quell warnings
win32: Makefile for MinGW.

Suggested by: Mateusz Czaplinski <czapkofan@gmail.com>
unifdef: fix type mismatch in debug() calls.

Adapted from a similar fix by Jörg Sonnenberger <joerg@NetBSD.org>
unifdefall: No need to use `basename`.

Obtained-from: David O'Brien <obrien@FreeBSD.org>
unifdef.1: Remove superfluous paragraph macro.

Obtained-from: Joel Dahl <joel@FreeBSD.org>
web: bump prerelease version again