mesa: Fix printf-like warning.
diff --git a/src/mesa/program/program_parse.y b/src/mesa/program/program_parse.y
index fb6ef85..cf621ae 100644
--- a/src/mesa/program/program_parse.y
+++ b/src/mesa/program/program_parse.y
@@ -2628,7 +2628,7 @@
 
    err_str = make_error_string("glProgramStringARB(%s)\n", s);
    if (err_str) {
-      _mesa_error(state->ctx, GL_INVALID_OPERATION, err_str);
+      _mesa_error(state->ctx, GL_INVALID_OPERATION, "%s", err_str);
       free(err_str);
    }