Reviewed by Eric Seidel.

        [GTK] Initial build support for WebGL
        https://bugs.webkit.org/show_bug.cgi?id=51716

        * configure.ac: Add a configure option for WebGL.
2011-01-06  Martin Robinson  <mrobinson@igalia.com>

        Reviewed by Eric Seidel.

        [GTK] Initial build support for WebGL
        https://bugs.webkit.org/show_bug.cgi?id=51716

        Add initial build support for WebGL and insert bits of implementation
        necessary for clean compilation into GraphicsContext3D.

        No new tests. This is just a build change.

        * GNUmakefile.am: Add missing files to the source lists.
        * platform/graphics/GraphicsContext3D.h: Include IntSize.h as it's used below.
        Include typedefs necessary for WebGL on GTK+ and consolidate typdefs which are the
        same across different platforms. X11 headers define the VERSION symbol, so it's
        necessary to undefine it, since it's used as an enum value.

git-svn-id: http://svn.webkit.org/repository/webkit/trunk@75209 268f45cc-cd09-0410-ab3c-d52691b4dbfc