cantata: fix build failure (close #2723)

We were one directory too high for configure.
ncmpc: propable fix for x86_64-darwin build error

@vcunat fixed syntax a bit. Close #2761.
swig: enable on Darwin (close #2326)

Verified on OS X 10.9.2 to build and check, dependents build fine too.

@vcunat enabled doCheck as it works for him on x86_64-linux;
also did style nitpick modification, and changed platforms to .all
according to the homepage http://www.swig.org/compat.html
Fixed link to installation instructions in README
Merge pull request #2763 from pSub/patch-1

Fixed link to installation instructions in README
webkitgtk: update to 2.4.3 (close #2640)
xorg: maintenance updates of a few modules
mesa: maintenance update 10.1.3 -> .4