Monkeyiq/2014/aug/travisosxpack

This is an update of the PR https://github.com/fontforge/fontforge/pull/1662 but is done on a branch that was first pushed to the mainline fontforge repository. I don't particularly like this design, in the past I have created branches in my fork of fontforge and generated PRs from there. Travis CI does not allow secure environment variables to be shown to builds from forks, see http://docs.travis-ci.com/user/encryption-keys/. I understand why Travis CI does this, and it makes sense. Once I get package building going I might look at having Travis CI build my fork, and branches in it rather than the mainline fontforge. The issue there is a slightly odd one that as far as I can see you would have to create a PR in your own fork against it's master for the Travis build to work there, then create a PR (call it PR2) against the fontforge repo citing the first PR to show that PR2 can pass CI and build a package.



Are you sure we want hard overrides for these variables rather than setting them if unset? I'm not particularly familiar with homebrew, but, when I'm building stuff from source, I often need to set non-standard environment variables, and this might make custom builds a bit more difficult.