Remove references to platform 'mac'

The 'mac' platform (that is, os.name == 'mac') was used for the MacOS 9 port,
which is no longer supported (as of Python 2.4 IIRC).
diff --git a/Lib/tempfile.py b/Lib/tempfile.py
index 84ec6e0..b0fd87d 100644
--- a/Lib/tempfile.py
+++ b/Lib/tempfile.py
@@ -33,10 +33,6 @@
 import errno as _errno
 from random import Random as _Random
 
-if _os.name == 'mac':
-    import Carbon.Folder as _Folder
-    import Carbon.Folders as _Folders
-
 try:
     from cStringIO import StringIO as _StringIO
 except ImportError:
@@ -153,15 +149,7 @@
         if dirname: dirlist.append(dirname)
 
     # Failing that, try OS-specific locations.
-    if _os.name == 'mac':
-        try:
-            fsr = _Folder.FSFindFolder(_Folders.kOnSystemDisk,
-                                              _Folders.kTemporaryFolderType, 1)
-            dirname = fsr.as_pathname()
-            dirlist.append(dirname)
-        except _Folder.error:
-            pass
-    elif _os.name == 'riscos':
+    if _os.name == 'riscos':
         dirname = _os.getenv('Wimp$ScrapDir')
         if dirname: dirlist.append(dirname)
     elif _os.name == 'nt':