Build HHVM-3.2.4b / merge snapshot upstream

- remove the patches, already upstream
- EOF patch update
- optimized CFLAG gcc debug
- `objective-caml` (hack lang work)
- Build with gcc48/gcc49 compiler.
- Speed up the build by precompiling headers.
- Enable minimal size release build.
- Revert debug hhvm flags, Enable debug build (default Release).