Remove -Dmacosx (on OSX only, obviously).

Reported by J. Lewis Muir on pkgsrc-users@ to fix build on 10.8.
Does not change behavior on 10.7; build fails much later at same place
either way.
Recursive PKGREVISION bump for serf-1.3.x (major shlib change).
Noted by tron.
Update to 1.21.2

Upstream changes:
Changes since 1.21.1[edit | edit source]
SECURITY: Fix extension detection with 2 .'s
SECURITY: Support for the 'gettoken' parameter to action=block and action=unblock, deprecated since 1.20, has been removed.
SECURITY: Sanitize ResourceLoader exception messages
Purge upstream caches when deleting file assets.
Unit test suite now runs the AutoLoader tests. Also fixed the autoloading entry for the PageORMTableForTesting class though it had no impact.
Updated www/mediawiki to 1.21.2