glthread: qualify the *cmd unmarshal parameter with restrict

This seems like a logical thing to do. Clearly the memory can't be
accessed with any other pointer.

Acked-by: Adam Jackson <ajax@redhat.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/21777>

src/mapi/glapi/gen/gl_marshal.py

@@ -191,7 +191,7 @@ class PrintCode(gl_XML.gl_print_base):
 
         out('uint32_t')
         out(('_mesa_unmarshal_{0}(struct gl_context *ctx, '
-             'const struct marshal_cmd_{0} *cmd)').format(func.name))
+             'const struct marshal_cmd_{0} *restrict cmd)').format(func.name))
         out('{')
         with indent():
             for p in fixed_params:

src/mapi/glapi/gen/gl_marshal_h.py

@@ -70,7 +70,7 @@ class PrintCode(gl_XML.gl_print_base):
             if flavor in ('custom', 'async'):
                 print('struct marshal_cmd_{0};'.format(func.name))
                 print(('uint32_t _mesa_unmarshal_{0}(struct gl_context *ctx, '
-                       'const struct marshal_cmd_{0} *cmd);').format(func.name))
+                       'const struct marshal_cmd_{0} *restrict cmd);').format(func.name))
 
             if flavor in ('custom', 'async', 'sync') and not func.marshal_is_static():
                 print('{0} GLAPIENTRY _mesa_marshal_{1}({2});'.format(func.return_type, func.name, func.get_parameter_string()))