gtkglextmm: fixed by removing '-D*DISABLE_DEPRECATED' through GCC_WRAPPER_REMOVE

Note:

error: 'GdkSpanFunc' has not been declared

http://bugs.gentoo.org/show_bug.cgi?id=342905
https://bugzilla.gnome.org/show_bug.cgi?id=636831

gtk+/gtkglextmm/gtkglextmm.conf

@@ -2,6 +2,7 @@
 # This copyright note is auto-generated by ./scripts/Create-CopyPatch.
 #
 # Filename: package/.../gtkglextmm/gtkglextmm.conf
+# Copyright (C) 2011 The OpenSDE Project
 # Copyright (C) 2006 The T2 SDE Project
 #
 # More information can be found in the files COPYING and README.
@@ -13,3 +14,6 @@
 # --- SDE-COPYRIGHT-NOTE-END ---
 
 var_append confopt ' ' "--disable-gtkglext-test"
+
+# avoid error: 'GdkSpanFunc' has not been declared
+var_append GCC_WRAPPER_REMOVE ' ' '-D*DISABLE_DEPRECATED'