* os.py: _exit doesn't exist in all variations of posix
* Added fcmp() to test_support.py and use it in test*.py
diff --git a/Lib/os.py b/Lib/os.py
index 556268f..dc1ef5a 100644
--- a/Lib/os.py
+++ b/Lib/os.py
@@ -18,7 +18,10 @@
 
 try:
 	from posix import *
-	from posix import _exit
+	try:
+		from posix import _exit
+	except ImportError:
+		pass
 	name = 'posix'
 	curdir = '.'
 	pardir = '..'