[MSVC] Use POSIX compliant getopt version from mingw64. * src/build-msvctools/Makefile (getopt.c, getopt.h): Use versions from mingw64, as they're POSIX compliant. (posixcompat.lib): New target library, replaces dirent.lib and getopt.lib. (dirent.lib, getopt.lib): Removed targets. * src/build-msvctools/getopt.diff: Removed obsolete patch. * src/build-msvctools/cc-msvc.cc: Links against posixcompat.lib instead of dirent.lib * src/build-msvctools/unistd.h: Include getopt.h, for POSIX compliance.

mxe.cc