Issue #8600: fix test_gdb failures when gdb issues some spurious warnings.
diff --git a/Lib/test/test_gdb.py b/Lib/test/test_gdb.py
index 907d6ef..388f240 100644
--- a/Lib/test/test_gdb.py
+++ b/Lib/test/test_gdb.py
@@ -119,6 +119,11 @@
 
         # Ignore some noise on stderr due to the pending breakpoint:
         err = err.replace('Function "%s" not defined.\n' % breakpoint, '')
+        # Ignore some other noise on stderr (http://bugs.python.org/issue8600)
+        err = err.replace("warning: Unable to find libthread_db matching"
+                          " inferior's thread library, thread debugging will"
+                          " not be available.\n",
+                          '')
 
         # Ensure no unexpected error messages:
         self.assertEquals(err, '')