* Make patches/wxwidgets-3.0.2_macosx_yosemite.patch usable.  There were
  complaints here before that the patch does not work because it is a
  "metapatch" that tries to patch another patch (which is not in the tree
  and therefore fails). With this change, it becomes a normal patch again,
  that can be applied to the wxWidgets source tree as described in
  Documentation/compiling/mac-osx.txt.
* Make scripts/library-repos-install.sh compatible with OSX: This involves
  checking for the correct option to enable extended regular expressions in
  sed during detect_pretty_repos, as the script uses "-r", which is only
  available in GNU sed. The sed shipped with Mac OSX is an older BSD descendant
  sed which needs "-E". This change has been tested to work on Mac OSX 10.10.1
  and on an up-to-date Arch Linux.  I also changed the error message during
  --install-prerequisites to inform users without apt-get or yum which programs
  need to be installed to use the script.
* Add the execute flag to scripts/osx_build_wx.sh: At the moment, after
  fetching the source with bzr, one has to chmod the file by hand. This
  change change ensures consistency between the script and the build docs
  for OSX, which assumes the script to be executable.