fix for older glib-2.0 versions to build with recent autotools

fix for older glib-2.0 versions to build with recent autotools

the attached patch bundles a single fix for glib-2.0
for recipes built upon glib tarballs 2.6.4 to 2.20.4.
later versions have the problem fixed in tarball (e.g. 2.22.1 and newer).

the problem happens when you need to update autotools
for some other reason (e.g. building some newer package)
whilst not wanting to update glib at the very same time.
it manifests by a badly clobbered "fi" in configure step
and thus a still open nesting level when the script ends.
the auto tools generated script exposes "fiAC_..." that
originates from a too extensive use of the "dnl" statemnt.
that construct is only critical with newer auto tools.

the fix removes those problematic extra keyword.

regards, Alex.

see for reference:
http://bugs.gentoo.org/show_bug.cgi?id=307775
http://git.gnome.org/browse/glib/commit/?id=c24f6e55276fac68b08df34b0d350f65afe994d9

Signed-off-by: Khem Raj <raj.khem@gmail.com>