Commit 3ebee3b1 defined assert() as g_assert(), but when we build
the VSS DLL component of QGA (to handle fsfreeze) we do not include
glib, which results in breakage when building with VSS support enabled.

Fix this by including glib (along with the -lintl and -lws2_32
dependencies it brings).

Since the VSS DLL is built statically, this introduces an additional
dependency on static glib and supporting libs for the mingw environment
(possibly why we didn't include glib originally), but VSS support
already has very specific prerequisites so it shouldn't affect too many
build environments.

Since the VSS DLL code does use qemu/osdep.h, this should also help
avoid future breakages and possibly allow for some clean ups in current
VSS code.

Suggested-by: Daniel P. Berrangé <berrange@redhat.com>
Cc: Daniel P. Berrangé <berrange@redhat.com>
Cc: qemu-stable@nongnu.org
Signed-off-by: Michael Roth <mdroth@linux.vnet.ibm.com>