Fix test_compiler.py that was using unittest.__file__ to find Lib/ (unittest is now a package).
diff --git a/Lib/test/test_compiler.py b/Lib/test/test_compiler.py
index c257f02..6394b53 100644
--- a/Lib/test/test_compiler.py
+++ b/Lib/test/test_compiler.py
@@ -23,7 +23,9 @@
         # to generate some kind of code for it.
 
         next_time = time.time() + _PRINT_WORKING_MSG_INTERVAL
-        libdir = os.path.dirname(unittest.__file__)
+        # warning: if 'os' or 'test_support' are moved in some other dir,
+        # they should be changed here.
+        libdir = os.path.dirname(os.__file__)
         testdir = os.path.dirname(test.test_support.__file__)
 
         for dir in [libdir, testdir]: