configure.ac: Fix the missing COGL_HAS_GLES[12] defines
configure.ac: Fix the missing COGL_HAS_GLES[12] defines

In 7fae8ac051 the two cogl-defines.h files from GLES and GL were
unified. However this missed out the COGL_HAS_GLES[12] defines from
GLES. The configure.ac still made an AC_SUBST for the right version
but the replacement was never put in any headers. This fixes it so
that instead of directly calling AC_SUBST the value is now put into a
variable which later gets added to COGL_DEFINES so that it will end up
in cogl-defines.h

GNOME/clutter,ebassi/clutter,djdeath/clutter-multithreaded,heysion/clutter-clone,nobled/clutter,djdeath/clutter-android,spatulasnout/clutter,dlespiau/clutter,heysion/clutter-clone,Distrotech/clutter,kerrickstaley/clutter-vala,GNOME/clutter,heysion/clutter-clone,djdeath/clutter,Distrotech/clutter,kerrickstaley/clutter-vala,dlespiau/clutter,jigpu/clutter,Distrotech/clutter,dlespiau/clutter,jigpu/clutter,djdeath/clutter,nobled/clutter,kerrickstaley/clutter-vala,djdeath/clutter,collects/clutter,djdeath/clutter-android,djdeath/clutter-multithreaded,spatulasnout/clutter,collects/clutter,ebassi/clutter,GNOME/clutter,rkudiyarov/clutter_osx,Distrotech/clutter,djdeath/clutter-android,GNOME/clutter,djdeath/clutter-multithreaded,Distrotech/clutter,spatulasnout/clutter,djdeath/clutter-android,jigpu/clutter,heysion/clutter-clone,djdeath/clutter-android,djdeath/clutter-multithreaded,rkudiyarov/clutter_osx,heysion/clutter-clone,collects/clutter,rkudiyarov/clutter_osx,spatulasnout/clutter,spatulasnout/clutter,djdeath/clutter,djdeath/clutter,ebassi/clutter,GNOME/clutter,collects/clutter,ebassi/clutter,djdeath/clutter,jigpu/clutter,ebassi/clutter,kerrickstaley/clutter-vala,nobled/clutter,jigpu/clutter,rkudiyarov/clutter_osx,collects/clutter,jigpu/clutter,Distrotech/clutter