Issue #7042:  Fix test_signal failure on OS X 10.6 64-bit builds
(and also, with luck, on the x86 FreeBSD buildbot), by making sure
that some user time is used in test_itimer_virtual.
diff --git a/Lib/test/test_signal.py b/Lib/test/test_signal.py
index 4368375..df0828d 100644
--- a/Lib/test/test_signal.py
+++ b/Lib/test/test_signal.py
@@ -361,6 +361,8 @@
         signal.setitimer(self.itimer, 0.3, 0.2)
 
         for i in xrange(100000000):
+            # use up some virtual time by doing real work
+            _ = pow(12345, 67890, 10000019)
             if signal.getitimer(self.itimer) == (0.0, 0.0):
                 break # sig_vtalrm handler stopped this itimer