From: Pasi K?rkk?inen
Subject: [PATCH] fix SDL OpenGL segfault with DRI/Mesa drivers and Glew

Hello!

The attached patch fixes a bug in SDL which causes SDL to crash in
X11_GL_Shutdown() if you are using DRI/Mesa drivers AND glew
(http://glew.sf.net).

The bug is caused by a namespace collision affecting dlsym() to fetch wrong
pointer for glXReleaseBuffersMESA() (uninitialized pointer from glew because
the extension is NOT supported by the driver) and then SDL calling it in
X11_GL_Shutdown().

SDL should check if the glXReleaseBuffersMESA() is really supported by the
driver (from the extensions string) before calling it.

Attached patch adds extension string parsing to check if
glXReleaseBuffersMESA() is really supported (and this way
prevents the segfault).

Availability of the extensions should be _always_ checked from the
extensions string rather than using dlsym()!

Please add it to the next version of SDL.

Thanks to gltron and author of glew to help fixing this.

--HG--
extra : convert_revision : svn%3Ac70aab31-4412-0410-b14c-859654838e24/trunk%40639