[gtk/wip/baedert/for-master] testgtk: Add G_GNUC_NORETURN to usage()

[Timm Bäder <baedert src gnome org>]

commit ec0947fdb2032d6ad47980e7087f4db9d8824a66
Author: Timm Bäder <mail baedert org>
Date:   Mon May 18 18:55:26 2020 +0200

    testgtk: Add G_GNUC_NORETURN to usage()

 tests/testgtk.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)
---
diff --git a/tests/testgtk.c b/tests/testgtk.c
index a296f5167f..3b035388ba 100644
--- a/tests/testgtk.c
+++ b/tests/testgtk.c
@@ -6154,7 +6154,7 @@ do_bench (char* what, int num)
     }
 }
 
-static void 
+static void G_GNUC_NORETURN
 usage (void)
 {
   fprintf (stderr, "Usage: testgtk [--bench ALL|<bench>[:<count>]]\n");