mesa_glinterop: allow building without X and related headers

mesa_glinterop: allow building without X and related headers

This commit effectively reverts c10dcb2ce837922c6ee4e191e6d6202098a5ee10
and fixes the typedef redefinition which inspired it.

In order to prevent requiring X packages at build time earlier commit
forward declared the required X/GLX typedefs. Since that approach
introduced typedef redefinition (a C11 feature) it was reverted.

To avoid the redefinition while _not_ mandating X and related headers
forward declare the structs and use those through the header.

As anyone uses the mesa interop header they ensure that the X (or others
in terms of EGL) headers are included, which ensures that everything is
resolved within the compilation unit.

Cc: Vinson Lee <vlee@freedesktop.org>
Cc: "12.0" <mesa-stable@lists.freedesktop.org>
Cc: Tapani Pälli <tapani.palli@intel.com>
Cc: Chih-Wei Huang <cwhuang@android-x86.org>
Fixes: c10dcb2ce837 ("Revert "mesa_glinterop: remove inclusion of GLX
header"")
Fixes: 8472045b16b3 ("mesa_glinterop: remove inclusion of GLX header")
Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=96770
Signed-off-by: Emil Velikov <emil.velikov@collabora.com>
Tested-by: Vinson Lee <vlee@freedesktop.org>
Reviewed-by: Tapani Pälli <tapani.palli@intel.com>