Make the utf8 manifest optional (on by default and
explicitly off with --disable-win32-utf8-manifest)
in the mingw hosts.

Also eliminate duplication between the 32-bit and
64-bit mingw hosts by putting them both in the
same branch and special-case only the 64-bit long
long setting.

PR mingw/111170
PR mingw/108865

Signed-off-by: Costas Argyris <costas.argyris@gmail.com>
Signed-off-by: Jonathan Yong <10walls@gmail.com>

gcc/Changelog:

	* configure.ac: Handle new --enable-win32-utf8-manifest
	option.
	* config.host: allow win32 utf8 manifest to be disabled
	by user.
	* configure: Regenerate.

(cherry picked from commit 4f1ebd54)