Homebrew SFML links itself with @rpath/ instead of the dylib path,
update the mac linking and bundling script to handle that case, also
move it from src/wx/tools/osx to tools/osx now that wx is the primary
port.
This fix is temporary and I will write a better one that takes
DYLD_LIBRARY_PATH and such into account, but will suffice for linking
Homebrew libs for now. The script needs more work in general.
Rafael Kitover