We need different export decorators for the different libs.
For now no actual change though, just rename before the release,
and add prelude headers to define the new decorator to GST_EXPORT.
Except for gst/gl/gstglfuncs.h
It is up to the client app to include these headers.
It is coherent with the fact that gstreamer-gl.pc does not
require any egl.pc/gles.pc. I.e. it is the responsability
of the app to search these headers within its build setup.
For example gstreamer-vaapi includes explicitly EGL/egl.h
and search for it in its configure.ac.
For example with this patch, if an app includes the headers
gst/gl/egl/gstglcontext_egl.h
gst/gl/egl/gstgldisplay_egl.h
gst/gl/egl/gstglmemoryegl.h
it will *no longer* automatically include EGL/egl.h and GLES2/gl2.h.
Which is good because the app might want to use the gstgl api only
without the need to bother about gl headers.
Also added a test: cd tests/check && make libs/gstglheaders.check
https://bugzilla.gnome.org/show_bug.cgi?id=784779
- xcb is supposedly thread-safe!
videotestsrc ! glimagesink now doesn't spuriously result in a
'call XInitThreads()' error however if anybody else is using X11,
then XInitThreads() still needs to be called and multiple glimagesink's
still need XInitThreads().
Everything still takes libX11 handles as they are compatible with the xcb
variants. Unfortunately we cannot move fully over to xcb due to GLX being
entirely based on Xlib. It's also impossible to transform a xcb_connection
to a Display which means we require X11 handles.
GstGLDisplayX11 holds the display connection and name. Each thread requires
it's own X11 Display connection (initialised from name) due to the fact that
we do not want to call XInitThreads(). Doing so would result in segfaults
when integrating with GUI toolkits Gtk, Qt, etc.
The Display connection is for OpenGL platforms where a constant display is
required in order to share contexts (egl). In the case of a wrapped context
(added later), we do not have GstGLWindow to retreive the display from so a
'master' connection is used instead.
