Add GLIB_ASSERT_SET() as a helper for adding "must be set when

Add GLIB_ASSERT_SET() as a helper for adding "must be set when

Wed Dec 11 17:00:20 2002  Owen Taylor  <otaylor@redhat.com>

        * acglib.m4 (ac_compile): Add GLIB_ASSERT_SET() as
        a helper for adding "must be set when cross-compiling"
        errors.

        * configure.in: For all cached variables without defaults,
        error out if they aren't set.