Issue #12326: refactor usage of sys.platform

 * Use str.startswith(tuple): I didn't know this Python feature, Python rocks!
 * Replace sometimes sys.platform.startswith('linux') with
   sys.platform == 'linux'
 * sys.platform doesn't contain the major version on Cygwin on Mac OS X
   (it's just 'cygwin' and 'darwin')
diff --git a/Lib/test/test_fcntl.py b/Lib/test/test_fcntl.py
index 6e425aa..29af99c 100644
--- a/Lib/test/test_fcntl.py
+++ b/Lib/test/test_fcntl.py
@@ -23,9 +23,8 @@
     else:
         start_len = "qq"
 
-    if (any(sys.platform.startswith(prefix)
-            for prefix in ('netbsd', 'freebsd', 'openbsd', 'bsdos'))
-        or sys.platform in ('Darwin1.2', 'darwin')):
+    if (sys.platform.startswith(('netbsd', 'freebsd', 'openbsd', 'bsdos'))
+        or sys.platform == 'darwin'):
         if struct.calcsize('l') == 8:
             off_t = 'l'
             pid_t = 'i'