mesa: check allocation failures in new_transform_feedback()

Signed-off-by: Samuel Pitoiset <samuel.pitoiset@gmail.com>
Reviewed-by: Timothy Arceri <tarceri@itsqueeze.com>

src/mesa/main/transformfeedback.c

@@ -207,7 +207,11 @@ static struct gl_transform_feedback_object *
 new_transform_feedback(struct gl_context *ctx, GLuint name)
 {
    struct gl_transform_feedback_object *obj;
+
    obj = CALLOC_STRUCT(gl_transform_feedback_object);
+   if (!obj)
+      return NULL;
+
    _mesa_init_transform_feedback_object(obj, name);
    return obj;
 }