Some fixes for OS X 10.9 Mavericks

I've recently upgraded to OS X 10.9 and Xcode 5. gcc and g++ are now just aliases for clang. Currently crossbridge (futures branch) fails to build in this environment. Here is a bunch of fixes from me to make crossbridge buildable again (up to some point, tr target still fails). It would be nice if someone could test my changes in old environment (OS X 10.8.5 and Xcode 4.6.3)