This adds a library that can be used instead of libGLESv2.so to provide
symbols for the GLES 2.0 api. This can be used for convenience when
using the cogl_gles2_context_ api since you don't need to manually go
through a CoglGLES2Vtable when calling the gles2 api so it should be
easier to port existing gles2 code to integrate with Cogl.
Reviewed-by: Neil Roberts <neil@linux.intel.com>
(cherry picked from commit 80d7599a2acefca7d01d8d7de9df524278ef72c5)
-Create a pre-defined cogl/cogl-gl-header.h(.win32) that is to be used on
any Windows builds, and adapt the MSVC build process to set up and use
that file.
-Fix up glib-mkenums code generation .bat file that is generated during
"make"/"make dist", like the autotools-based builds.
-Since cogl/cogl-defines.h now contain versionioning info, and it no longer
directly includes the GL headers, update the pre-configured
cogl-defines.h[.win32|.win32_SDL] and use autotools to fill in the
versioning info during "make"/"make dist".
-Fix up cogl/cogl-pango.rc.in so that they reflect the cogl-2.x versioning
stuff correctly and versioning info can be filled in correctly during
"make"/"make dist"
Reviewed-by: Robert Bragg <robert@linux.intel.com>
(cherry picked from commit 7ff42bb1c5280b0f53370f8d94ef5f10c9f39e2f)
The stock 1.2.x version of SDL only supports regular OpenGL. The
version on WebOS is specially patched to add some extra API to request
a GLES1 or GLES2 context. This patch adds a configure check to detect
when Cogl is being built with the patched version of SDL. In that case
it will additionally allow the gles1 and gles2 drivers and set the
right video mode attributes to get the corresponding context.
Reviewed-by: Robert Bragg <robert@linux.intel.com>
(cherry picked from commit 3726c60deab2bd94617a562abb63f735627a25e4)
This makes the test-cogl-perf test from clutter into a standalone Cogl
benchmark.
Reviewed-by: Neil Roberts <neil@linux.intel.com>
(cherry picked from commit 1684a040b238ebae140e827f4003f2d2867c04f3)
The check for whether the compiler supports _Static_assert didn't work
properly because the AC_TRY_COMPILE function puts the source
definition in its own main function. The test therefore ends up
declaring a nested main function which GCC allows. If _Static_assert
isn't available then it just looks like an implicit declaration of a
function which only causes a warning in GCC so it would still compile.
This patch changes it to use AC_COMPILE_IFELSE instead. This macro
makes it possible to specify the complete source code so
_Static_assert can be called from the global scope. AC_LANG_PROGRAM is
used to generate the program. For extra aesthetics it now also
generates a 'checking for...' message while the script is running.
Reviewed-by: Robert Bragg <robert@linux.intel.com>
(cherry picked from commit 9657938c3083a782234e1e9f05ab5ae88a6bc5ab)
This adds a _COGL_STATIC_ASSERT macro that can be used for compile time
assertions in C code. If supported by the compiler this macro uses
_Static_assert so that a message can be printed out if the assertion
fails.
Reviewed-by: Neil Roberts <neil@linux.intel.com>
(cherry picked from commit 465b39a764f2720e77678cafa56acb0e69007ffd)
This splits the GL header inclusion from cogl-defines.h into a
separate headear called cogl-gl-header.h which we will only include
internally. That way we don't leak GL declarations out of our public
headers. The texture functions that were using GLenum and GLuint in
the public header have now changed to just use unsigned int. Note
however that if an EGL winsys is enabled then it will still publicly
include an EGL header. This is a bit more awkward to fix because we
have public API which returns an EGLDisplay and we can't determine
what type that is.
There is also a conformance test which just verifies that no GL header
has been included while compiling. The test isn't added to
test-conform-main because it doesn't actually test anything at
runtime.
Reviewed-by: Robert Bragg <robert@linux.intel.com>
(cherry picked from commit ef5680d3fda5df929dbd0b420c8f598ded58dfee)
It looks like the then-clause of the AS_IF macro needs to be in square
brackets otherwise the configure script gets generated wrong and you
get this output when you run it:
configure: line 17339: COGL_PANGO_DEP_CFLAGS: command not found
configure: line 17340: C: command not found
configure: line 17341: COGL_PANGO_DEP_LIBS: command not found
configure: line 17342: linker: command not found
Reviewed-by: Robert Bragg <robert@linux.intel.com>
The KMS platform accesses all of it's GL symbols via the indirection
through the Cogl context so there is no need to link against it
directly. This helps when trying to use Cogl with GLES where pulling
in Xlib via libGL is potentially a problem.
Reviewed-by: Robert Bragg <robert@linux.intel.com>
This option to GCC makes it give a warning whenever a global function
is defined without a declaration. This should catch cases were we've
defined a function but forgot to put it in a header. In that case it
is either only used within one file so we should make it static or we
should declare it in a header.
The following changes where made to fix problems:
• Some functions were made static
• cogl-path.h (the one containing the 1.0 API) was split into two
files, one defining the functions and one defining the enums so that
cogl-path.c can include the enum and function declarations from the
2.0 API as well as the function declarations from the 1.0 API.
• cogl2-clip-state has been removed. This only had one experimental
function called cogl_clip_push_from_path but as this is unstable we
might as well remove it favour of the equivalent cogl_framebuffer_*
API.
• The GLX, SDL and WGL winsys's now have a private header to define
their get_vtable function instead of directly declaring in the C
file where it is called.
• All places that were calling COGL_OBJECT_DEFINE need to have the
cogl_is_whatever function declared so these have been added either
as a public function or in a private header.
• Some files that were not including the header containing their
function declarations have been fixed to do so.
• Any unused error quark functions have been removed. If we later want
them we should add them back one by one and add a declaration for
them in a header.
• _cogl_is_framebuffer has been renamed to cogl_is_framebuffer and
made a public function with a declaration in cogl-framebuffer.h
• Similarly for CoglOnscreen.
• cogl_vdraw_indexed_attributes is called
cogl_framebuffer_vdraw_indexed_attributes in the header. The
definition has been changed to match the header.
• cogl_index_buffer_allocate has been removed. This had no declaration
and I'm not sure what it's supposed to do.
• CoglJournal has been changed to use the internal CoglObject macro so
that it won't define an exported cogl_is_journal symbol.
• The _cogl_blah_pointer_from_handle functions have been removed.
CoglHandle isn't used much anymore anyway and in the few places
where it is used I think it's safe to just use the implicit cast
from void* to the right type.
• The test-utils.h header for the conformance tests explicitly
disables the -Wmissing-declaration option using a pragma because all
of the tests declare their main function without a header. Any
mistakes relating to missing declarations aren't really important
for the tests.
• cogl_quaternion_init_from_quaternion and init_from_matrix have been
given declarations in cogl-quaternion.h
Reviewed-by: Robert Bragg <robert@linux.intel.com>
This patch reworks our conformance testing framework because it seems
that glib's gtesting framework isn't really well suited to our use case.
For example we weren't able to test windows builds given the way we
were using it and also for each test we'd like to repeat the test
with several different environments so we can test important driver and
feature combinations.
This patch instead switches away to a simplified but custom approach for
running our unit tests. We hope that having a more bespoke setup will
enable us to easily extend it to focus on the details important to us.
Notable changes with this new approach are:
We can now run 'make test' for our mingw windows builds.
We've got rid of all the test-*report* make rules and we're just left
with 'make test'
'make test' now runs each test several times with different driver and
feature combinations checking the result for each run. 'make test' will
then output a concise table of all of the results.
The combinations tested are:
- OpenGL Fixed Function
- OpenGL ARBfp
- OpenGL GLSL
- OpenGL No NPOT texture support
- OpenGLES 2.0
- OpenGLES 2.0 No NPOT texture support
Reviewed-by: Neil Roberts <neil@linux.intel.com>
This adds two new functions:
void
cogl_poll_get_info (CoglContext *context,
CoglPollFD **poll_fds,
int *n_poll_fds,
gint64 *timeout);
void
cogl_poll_dispatch (CoglContext *context,
const CoglPollFD *poll_fds,
int n_poll_fds);
The application is expected to call the first function whenever it is
about to block to go idle, and the second function whenever it comes
out of idle. This gives Cogl winsys's the ability poll file
descriptors for events. For example when handing swap complete
notifications, it can report that it needs to block on a file
descriptor.
The two functions are backed by winsys virtual functions. There are
currently no implementations. The default handler for get_info just
reports no file descriptors and an infinite timeout.
Reviewed-by: Robert Bragg <robert@linux.intel.com>
This skips the pkg-config check for COGL_PANGO_DEPS if
--disable-cogl-pango was explicitly passed to ./configure.
Reviewed-by: Neil Roberts <neil@linux.intel.com>
The SDL winsys was missing a few minor features, such as the
implementation. This patch adds that in.
Reviewed-by: Robert Bragg <robert@linux.intel.com>
Eventually we might want to have an XCB-based EGL winsys. We already
have xlib-specific API in CoglRenderer (eg, to set a foreign display)
so the application needs to be able to specifically select between XCB
and XLIB.
This also removes the POWERVR part while renaming
COGL_HAS_EGL_PLATFORM_POWERVR_X11_SUPPORT to
COGL_HAS_EGL_PLATFORM_XLIB_SUPPORT because the winsys is equally
applicable to Mesa.
Reviewed-by: Robert Bragg <robert@linux.intel.com>
It looks like the documentation for this option has a copy-and-paste
bug from the wayland documentation.
Reviewed-by: Robert Bragg <robert@linux.intel.com>
The #ifdefs in cogl-winsys-egl have been changed so that they
additionally check renderer->winsys_vtable->id for the corresponding
winsys ID so that multiple EGL platforms can be enabled.
The is a stop-gap solution until we can move all of the EGL platforms
into their own winsys files with overrides of the EGL vtable. However
with this approach we can move one platform at a time which will make
it easier.
Reviewed-by: Robert Bragg <robert@linux.intel.com>
To start with this backend only supports creating a single CoglOnscreen
framebuffer and will automatically set is up to display fullscreen on
the first suitable crtc it can find.
To compile this backend - get some dribbly black candles, sacrifice a
goat and configure with: --enable-kms-egl-platform
Note: There is currently a problem with using GLES2 with this winsys
so you need to run with EGL_DRIVER=gl
Note: If you have problems with mesa crashing in XCB during
eglInitialize then you may need to explicitly run with EGL_PLATFORM=gbm
Reviewed-by: Robert Bragg <robert@linux.intel.com>
These are the VS 2008/2010 project files to build Cogl, with a README.txt
to explain the process involved.
Note that the Cogl and Cogl-Pango projects (and filters for VS2010) are
expanded with the correct source file listings during "make dist", which
is done to simplify maintenance of these project files.
-added preconfigured config.h(.win32.in), which is expanded with the
correct versioining info during autogen
-added preconfigued cogl/cogl-defines.h.win32
-added symbols files for cogl and cogl-pango
-Have configure.ac expand the config.h.win32.in into config.h.win32
with the correct versioning info, etc, and to include the Visual C++
project files for distribution
-Added rules in cogl/Makefile.am to expand the cogl VS 2008/2010 projects
and filters from the templates with up-to-date source file listings, to
distribute cogl-enum-types.c, cogl-enum-types.h to ease compilation and
to avoid depending on PERL on Windows installations.
-Added rules in cogl-pango/Makefile.am to expand the cogl-pango VS2008/
2010 projects and filters from the templates with up-to-date source file
listings.
-Added/edited various Makefile.am's in build to distribute the VS2008/2010
project files and associated items required for the build.
-Update .gitignore. There needs to be a pre-configured
config.h(.win32) and its template, config.h.win32.in for Visual C++
builds
https://bugzilla.gnome.org/show_bug.cgi?id=650020
Reviewed-by: Neil Roberts <neil@linux.intel.com>
Since we've had several developers from admirable projects say they
would like to use Cogl but would really prefer not to pull in
gobject,gmodule and glib as extra dependencies we are investigating if
we can get to the point where glib is only an optional dependency.
Actually we feel like we only make minimal use of glib anyway, so it may
well be quite straightforward to achieve this.
This adds a --disable-glib configure option that can be used to disable
features that depend on glib.
Actually --disable-glib doesn't strictly disable glib at this point
because it's more helpful if cogl continues to build as we make
incremental progress towards this.
The first use of glib that this patch tackles is the use of
g_return_val_if_fail and g_return_if_fail which have been replaced with
equivalent _COGL_RETURN_VAL_IF_FAIL and _COGL_RETURN_IF_FAIL macros.
Reviewed-by: Neil Roberts <neil@linux.intel.com>
This namespaces all of the examples and marks them for installation
if --enable-examples-install has been passed to ./configure. This
simplifies packaging the examples which can be quite convenient
for smoke testing Cogl on various platform.
https://bugzilla.gnome.org/show_bug.cgi?id=656755
Reviewed-by: Neil Roberts <neil@linux.intel.com>
G_DISABLE_DEPRECATED is only intended for developers of Cogl and it
sometimes breaks the build for people just trying to build a
release. This patch adds an option to enable deprecated Glib
features. By default it is enabled for non-git versions of Cogl.
The patch is based on similar code in Clutter except it adds the flags
to COGL_EXTRA_CFLAGS instead of having a separate variable.
Reviewed-by: Robert Bragg <robert@linux.intel.com>
This splits out the core CoglPipelineLayer support code from
cogl-pipeline.c into cogl-pipeline-layer.c; it splits out the debugging
code for dumping a pipeline to a .dot file into cogl-pipeline-debug.c
and it splits the CoglPipelineNode support which is shared between
CoglPipeline and CoglPipelineLayer into cogl-node.c.
Note: cogl-pipeline-layer.c only contains the layer code directly
relating to CoglPipelineLayer objects; it does not contain any
_cogl_pipeline API relating to how CoglPipeline tracks and manipulates
layers.
This makes a start on porting the Cogl conformance tests that currently
still live in the Clutter repository to be standalone Cogl tests that no
longer require a ClutterStage.
The main thing is that this commit brings in is the basic testing
infrastructure we need, so now we can port more and more tests
incrementally.
Since the test suite wants a way to synchronize X requests/replies and
we can't simply call XSynchronize in the test-utils code before we know
if we are really running on X this adds a check for an environment
variable named "COGL_X11_SYNC" in cogl-xlib-renderer.c and if it's set
it forces XSynchronize (dpy, TRUE) to be called.
By default the conformance tests are run off screen. This makes the
tests run much faster and they also don't interfere with other work you
may want to do by constantly stealing focus. CoglOnscreen framebuffers
obviously don't get tested this way so it's important that the tests
also get run on screen every once in a while, especially if changes are
being made to CoglFramebuffer related code. On screen testing can be
enabled by setting COGL_TEST_ONSCREEN=1 in your environment.
Cogl requires gobject and gmodule API, so we need to check for these and
add them to the pkg-config files as dependencies, otherwise building
Cogl with --as-needed (like modern distributions now do) will cause
build errors.
https://bugzilla.gnome.org/show_bug.cgi?id=656809
Reviewed-by: Robert Bragg <robert@linux.intel.com>
Only cogl-pango needs a dependency on pangocairo so we are now careful to
separate the pangocairo pkg-config flags from the others so we can avoid
having libcogl builds refer to them.
Reviewed-by: Neil Roberts <neil@linux.intel.com>
It's not necessary to generate cogl-display.h just for the GDL backend
and to change the inclusion of libgdl.h. We can just tweak the include
CFLAGS to put /usr/include/CE4100 in the search path when needed.
Previously this did not work because of a stay ',' at the end of the
COGL_EXTRA_CFLAGS int he configure.ac. This actually simplifies the
code, which is always good.
This also fixes out of tree builds.
https://bugzilla.gnome.org/show_bug.cgi?id=655724
Reviewed-by: Neil Roberts <neil@linux.intel.com>
We weren't defining CLUTTER_CEX100_LIBGDL_PREFIX in the configure.ac and
thus failing to compile when selecting the EGL/GDL winsys. Take the
opportunity to rename that to COGL_CEX100_LIBGDL_PREFIX
https://bugzilla.gnome.org/show_bug.cgi?id=655355
AC_CHECK_HEADER(S) for eglext.h need include egl.h as it may not be done
for you.
The patch tries to integrate with the previous work to check if
GLES/egl.h ir EGL/egl.h should be included for egl.h.
This adds 3 configure options to override the library name that gets
dlopened for GL, GLES and GLESv2. This could be useful for distro
maintainers who have an unusual name for the libraries (for example,
on OpenBSD the GL library appears to be called libGL.so.4). This could
at least be simpler than having to create a distro patch.
The configure options would be used like this:
./configure --with-gl-libname=libGL.so \
--with-gles1-libname=libGLESv1.so \
--with-gles2-libname=libGLESv2.so
https://bugzilla.gnome.org/show_bug.cgi?id=654593
Instead of using g_module_build_path with the short name of the GL
library (eg, "GL") and relying on glib to add the suffix and prefix,
the configure script now directly encodes the full name including the
version number (eg, "libGL.so.1"). This is necessary because distros
don't always install the non-versioned suffix for the library.
The GLES libraries are left without the version suffix because it's
not clear what should be placed here and I can't find any
documentation from Khronos to clarify this. Mesa seems to install a
file called libGLESv2.so.2 but the IMG SDK doesn't install any
versioned library. There is an example of dynamically loading
libGLESv2 in the Chromium source code and that does not use the
version suffix even though it does use the version suffix for GL. This
implies that it's at least fairly normal to load the unversioned name
for GLES.
https://bugzilla.gnome.org/show_bug.cgi?id=654593
Instead of only exposing COGL_HAS_GLX_SUPPORT internally in config.h we
now expose it though the public cogl-defines.h header.
Signed-off-by: Neil Roberts <neil@linux.intel.com>
--enable-uprof has been renamed to --enable-profile, make sure the help
string is updated accordingly.
Signed-off-by: Robert Bragg <robert@linux.intel.com>
The experimental 2.0 reference manual was setup with DOC_MODULE name of
"cogl" which conflicted with the 1.x API manual. This meant that when
running make install for both the reference manuals all the html files
would end up bundled together in the same location. The 2.0 API
reference now has a DOC_MODULE name of "cogl-2.0-experimental" the
corresponding -sections.txt and -docs.xml.in files have also been
renamed to match this.
Signed-off-by: Neil Roberts <neil@linux.intel.com>
The GL or GLES library is now dynamically loaded by the CoglRenderer
so that it can choose between GL, GLES1 and GLES2 at runtime. The
library is loaded by the renderer because it needs to be done before
calling eglInitialize. There is a new environment variable called
COGL_DRIVER to choose between gl, gles1 or gles2.
The #ifdefs for HAVE_COGL_GL, HAVE_COGL_GLES and HAVE_COGL_GLES2 have
been changed so that they don't assume the ifdefs are mutually
exclusive. They haven't been removed entirely so that it's possible to
compile the GLES backends without the the enums from the GL headers.
When using GLX the winsys additionally dynamically loads libGL because
that also contains the GLX API. It can't be linked in directly because
that would probably conflict with the GLES API if the EGL is
selected. When compiling with EGL support the library links directly
to libEGL because it doesn't contain any GL API so it shouldn't have
any conflicts.
When building for WGL or OSX Cogl still directly links against the GL
API so there is a #define in config.h so that Cogl won't try to dlopen
the library.
Cogl-pango previously had a #ifdef to detect when the GL backend is
used so that it can sneakily pass GL_QUADS to
cogl_vertex_buffer_draw. This is now changed so that it queries the
CoglContext for the backend. However to get this to work Cogl now
needs to export the _cogl_context_get_default symbol and cogl-pango
needs some extra -I flags to so that it can include
cogl-context-private.h
The README file is generated by the configure script so that it can
include the required dependency version numbers. However there was no
corresponding AC_SUBST calls for the versions so the README would be
left with @THESE_MARKERS@.
The "default" m4 conflicts with one of libtool's internal symbols, one
that is used to determine whether the -fPIC argument should be used;
this breaks compilation onf 64bit platforms.
https://bugzilla.gnome.org/show_bug.cgi?id=653615
Signed-off-by: Emmanuele Bassi <ebassi@linux.intel.com>
Signed-off-by: Neil Roberts <neil@linux.intel.com>
So that our released tarballs can contain filenames longer than 99
characters we tell automake to create tarballs using the ustar format.
This is newer than the default v7 format but still old enough to be
considered widely portable.
This adds a --enable-profile option which enables uprof based profiling.
It was also necessary to fixup a CLUTTER_ENABLE_PROFILING #ifdef in
cogl-context.c to renamed COGL_ENABLE_PROFILING instead. By default Cogl
doesn't output uprof reports directly, instead it assumes a higher level
toolkit will output a report. If you want a report from Cogl you can
export COGL_PROFILE_OUTPUT_REPORT=1 before running your app.
The latest version of uprof can be fetched from:
git://github.com/rib/UProf.git
This explicitly renames the cogl-2.0 reference manual to
cogl-2.0-experimental and renames the cogl-2.0 pkg-config file to
cogl-2.0-experimental.pc. Hopefully this should avoid
miss-understandings.
This adds an extra header that gets included from config.h where we
can add configuration defines. This is used to #undef 'near' and 'far'
when building for Windows so that we don't have to avoid using them as
variable names in the Cogl code.
This adds internal API to be able to wrap a wayland buffer as a
CoglTexture2D. There is a --enable-wayland-egl-server option to decide
if Cogl should support this feature and potentially any EGL based winsys
could support this through the EGL_KHR_image_base and
EGL_WL_bind_display extensions.
This moves the --enable-cairo check because it was put in the middle of
the logic that handles the --enable-debug option. This moves the
--enable-cairo check down after the --enable-debug logic and adds a
comment header to delimit the option like we have for other options.
Instead of the stub winsys being a special case set of #ifdef'd code
used when COGL_HAS_FULL_WINSYS wasn't defined, the stub winsys now
implements a CoglWinsysVtable like all other winsys backends (it's just
that everything is a NOP). This way we can get rid of the
COGL_HAS_FULL_WINSYS define and also the stub winsys can be runtime
selected whereas before it was incompatible with all other winsys
backends.
Until we have a standalone quartz winsys we don't want to define a
winsys name called "quartz" which is what the current --enable-quartz
option does. For now anyone building for OSX needs to use the stub
winsys and setup their own GL context.
The native window type of the EGL/Android winsys is ANativeWinow*. The
Android NDK gives you a pointer to this ANativeWindow and you just need
to configure that window using the EGLConfig you are choosing when
creating the context.
This means you have to know the ANativeWindow* window before creating
the context. This is solved here by just having a global variable you
can set with cogl_android_set_native_window() before creating the
context. This is a bit ugly though, and it conceptually belongs to the
OnScreen creation to know which ANativeWindow* to use. This would need a
"lazy context creation" mechanism, waiting for the user to create the
OnScreen to initialize the GL context.
Early implementations provided only a GLES/egl.h while Khronos's
implementer guide now states EGL/egl.h is the One. Some implementations
keep a GLES/egl.h wrapper around EGL/egl.h for backward compatibility
while others provide EGL/egl.h only.
Also took the opportunity to factorize a bit this inclusion in
cogl-defines.h.
When checking for EGL earlier in the configure script (ie EGL_CHECKED is
"yes"), we did not execute some EGL code. Let's split that code in two:
- A first part that has a last change to check for EGL
- A second one that defines variables and that should always been run
in an EGL build
GLES/glext.h and GLES2/gl2ext.h need to include GLES/gl.h and
GLES2/gl2.h respectively to get the GL types.
This used to work as autoconf used to only do a preprocessor pass in
AC_CHECK_HEADER(S), but now it also tries to compile a small test
program and thus the test failed.
Gtk-doc can be hard to install on Windows. This patch enables people wanting to
hack on Cogl itself from a Windows system to do so without the hassle to get
gtk-doc installed first.
The semantics of shadowing global variables is well defined and it gets
quite annoying to avoid them completely since there are too many
standard APIs with very poor namespacing.
Wayland now supports integration via standard eglSurfaces which makes it
possible to share more code with other EGL platforms. (though at some
point cogl-winsys-egl.c really needs to gain a more formal
CoglEGLPlatform abstraction so we can rein back on the amount of #ifdefs
we have.)
This pulls in the experimental cogl 2.0 reference manual from the
clutter repository since it wasn't included in the filter-branch when we
split cogl out.
When Cogl was sharing Clutter's configure script, it had a check for
the ffs function of libc so that it can provide a fallback if it is
not available. This fallback was missed in the split out so Cogl would
end up always using the fallback.
This removes all the remnants from being able to build Cogl standalone
while it was part of the Clutter repository. Now that Cogl has been
split out then standalone builds are the only option.
We now install cogl-pango-1.0 and cogl-pango-2.0 pkg-config files that
applications should optionally depend on if they want to use the
cogl_pango API.
For compatibility with the way we build Cogl as part of Clutter we now
substitute an empty MAINTAINER_CFLAGS variable. When building Cogl
standalone all our extra CFLAGS go through COGL_EXTRA_CFLAGS so the
separate MAINTAINER_CFLAGS aren't used, but automake will get confused
if a substitution isn't made.
