build_core: fix HG revision export

git-svn-id: https://rebeccablackos.svn.sourceforge.net/svnroot/rebeccablackos@2946 56e3d1a8-0179-4092-b3e2-9fbbcda0c0a9
gtk: continue on failed build

git-svn-id: https://rebeccablackos.svn.sourceforge.net/svnroot/rebeccablackos@2947 56e3d1a8-0179-4092-b3e2-9fbbcda0c0a9