[GB#629796] fix gdk/gtkglenumtypes.h.template

(cherry picked from commit b85a5f88d0861955dd05af4e6c7f5abee6f48ab2)
Signed-off-by: Emmanuele Bassi <ebassi@gnome.org>
Use autogen.sh

Follow the common patterns of all autotooled projects.
Update autotools configuration a bit

Fixes https://bugzilla.gnome.org/show_bug.cgi?id=616803
add missing gobject-introspection annotations

(cherry picked from commit f3175ae198816e5c5a80b9e8a1288dbf1de2f28c)
Signed-off-by: Emmanuele Bassi <ebassi@gnome.org>
add gobject-introspection support

(cherry picked from commit 8ba11ba74fbdf00fc2a719db175e054f4c96354c)

Signed-off-by: Emmanuele Bassi <ebassi@gnome.org>
Remove copy of introspection.m4

Rely on gobject-introspection as a configure-time dependency, like most
of the GNOME platform.
build: Do not disable deprecated symbols on Quartz

It's pointless, for an unmaintained library, and we don't do that for
any other backend, library, or examples.
Remove unexpanded GDKGLEXT_MULTIHEAD_SUPPORT symbol

It's not expanded any more.