Added SDL_opengl_glext.h to the list of headers to install.
diff --git a/Makefile.in b/Makefile.in
index e9962ac..a330831 100644
--- a/Makefile.in
+++ b/Makefile.in
@@ -70,6 +70,7 @@ HDRS = \
SDL_mutex.h \
SDL_name.h \
SDL_opengl.h \
+ SDL_opengl_glext.h \
SDL_opengles.h \
SDL_opengles2.h \
SDL_pixels.h \