encoding: improve handling of buggy getpreferredencoding() on Mac OS X Prior to version 2.7, calling locale.getpreferredencoding() would always return 'mac-roman' on Mac OS X. Previously, this was handled by a call to locale.setlocale(). Unfortunately, Python 2.6.5 and older have a bug where isspace() would incorrectly report True for 0x85 and 0xa0 after such a call. In order to fix this, we replace the previous _encodingfixup mapping to an _encodingfixers mapping. Rather than mapping encodings to their replacement, it maps them to a function returning the replacement. This allows us to provide an simplified implementation of getpreferredencoding() which extracts the expected encoding and restores the locale. This fix is based on a patch originally submitted by Martijn Pieters as well as feedback from Brodie Rao.