[clutter-gst] build: Link against -lGL when we know it's safe to

[Damien Lespiau <dlespiau src gnome org>]

commit c50263f81c233fbbf93f464848384de98787ae66
Author: Damien Lespiau <damien lespiau intel com>
Date:   Tue Aug 30 16:48:31 2011 +0100

    build: Link against -lGL when we know it's safe to
    
    We are using a gl call (glGetIntergerv). However, detecting wich GL
    headers and library to use is getting impossible (as nowedays, cogl even
    has a runtime selection of which library should be dlopened, so it could
    be either one of flavours of the GLES1 DSO or the GLES2 DSO, or the Big
    GL one).
    
    So, really, we should not have any direct GL call in clutter-gst. The
    solution is coming, but in the mean time, just link against -lGL when
    it's safe to assume so.

 clutter-gst/Makefile.am |    1 +
 configure.ac            |   22 ++++++++++++++++++++++
 2 files changed, 23 insertions(+), 0 deletions(-)
---
diff --git a/clutter-gst/Makefile.am b/clutter-gst/Makefile.am
index 06f2248..812f197 100644
--- a/clutter-gst/Makefile.am
+++ b/clutter-gst/Makefile.am
@@ -82,6 +82,7 @@ lib_LTLIBRARIES = libclutter-gst- CLUTTER_GST_MAJORMINOR@.la
 libclutter_gst_ CLUTTER_GST_MAJORMINOR@_la_LIBADD  = @CLUTTER_GST_LIBS@ $(GST_LIBS)
 libclutter_gst_ CLUTTER_GST_MAJORMINOR@_la_LDFLAGS =	\
 	$(CLUTTER_GST_LT_LDFLAGS)			\
+	$(GL_LDFLAGS)					\
 	-export-dynamic					\
 	-export-symbols-regex "^clutter_gst.*"		\
 	-rpath $(libdir)
diff --git a/configure.ac b/configure.ac
index a0d2fdb..782caf0 100644
--- a/configure.ac
+++ b/configure.ac
@@ -147,6 +147,28 @@ pkg_modules="gstreamer-$GST_MAJORMINOR >= $GSTREAMER_REQ_VERSION gstreamer-plugi
 PKG_CHECK_MODULES(GST, [$pkg_modules])
 
 dnl ========================================================================
+dnl GL inclusion and link. We depend on GL for the single glGetIntegerv()
+dnl call. The end goal is to get rid of it, but we can't just yet.
+
+dnl For now, we assume Clutter/Cogl includes the GL headers (whatever they
+dnl are). By the time they don't do that, we'll hopefully won't have any
+dnl direct GL dependency.
+
+dnl As for linking against -lGL, I believe Clutter always end up puttin libGL
+dnl in its exported CFLAGS, except when compiling against the NVidia library
+dnl (which does not have the 'gl' .pc file. For now, let's just add -lGL when
+dnl we are using the glx flavour, That should fix the vast majority of the
+dnl issues
+
+dnl Why don't we "just" link against GL? check the cogl/clutter configure.ac :)
+dnl Hopefully this will be enough for the time being.
+
+clutter_soname=`$PKG_CONFIG --variable soname_infix clutter-1.0`
+AS_CASE([$clutter_soname],
+        [glx], [AC_CHECK_LIB([GL], [glGetIntegerv], [GL_LDFLAGS="-lGL"])])
+AC_SUBST([GL_LDFLAGS])
+
+dnl ========================================================================
 
 m4_define([maintainer_flags_default], [yes])
 AC_ARG_ENABLE([maintainer-flags],