Merge 3.4 (test.support)
diff --git a/Lib/test/support/__init__.py b/Lib/test/support/__init__.py
index 77e2d76..1919082 100644
--- a/Lib/test/support/__init__.py
+++ b/Lib/test/support/__init__.py
@@ -1439,7 +1439,7 @@
     for opt in cflags.split():
         if opt.startswith('-O'):
             final_opt = opt
-    return final_opt != '' and final_opt != '-O0'
+    return final_opt not in ('', '-O0', '-Og')
 
 
 _header = 'nP'