Make _cogl_xlib_trap_errors re-entrant
    looks good

cogl-defines.h: Add a COGL_HAS_X11 define
    we should rename the internal COGL_HAS_XYZ_SUPPORT defines to COGL_HAS_XYZ_SUPPORT_INTERN
    we should possibly rename the public COGL_HAS_XYZ defines to COGL_HAS_XYZ_SUPPORT

Add a test case for CoglTexturePixmapX11
    looks good

Add -DCOGL_ENABLE_EXPERIMENTAL_API to Makefiles for Cogl and x11/glx
    looks good

Make the cogl-texture-pixmap-x11 API experimental
    Someone needs to do something about those _EXP suffixes :-)

Use guint32 instead of Pixmap in the public headers
    looks good

Revert "Add --include=xlib-2.0 for the introspection data of Cogl"
    looks good

Add cogl_texture_pixmap_set_damage_object
    looks good

clutter-x11-texture-pixmap: Use cogl_texture_pixmap_x11_set_damage_object
    code looks good
    the commit message has a slightly odd sentence structure

Fix cogl_damage_rectangle_union for empty damage regions
    looks good