I just noticed that after installing OS X 10.9, the g++ compiler links to the clang compiler. Is there anyway to revert back to gcc/g++?
It has been this way for a long time already. The "GCC" that came with 10.8 was really GCC front-end with LLVM back-end.
The best way to get GCC is via Homebrew. After the one-line homebrew install command on the bottom of the linked page, you just need:
$ brew install gcc49
Unlike macports, Homebrew doesn't clutter your system dirs and it's much better at managing versions and uninstalls. It also doesn't require the crutch known as sudo.
You'd have to install it from macports:
$ sudo port install gcc49
However I am not certain how you'd integrate gcc into Xcode 5, however you don't mention why you cannot use clang?
Accessible and up to date GCC packages are at http://hpc.sourceforge.net/
you can also get a g++ compiler from http://hpc.sourceforge.net/. They have the compiler in a pre-built package. Just download and follow their directions. Note you may need to change your executable PATH and have /usr/local/bin ahead of /usr/bin. This is to insure g++ calls the right compiler.
This is by design, and not new in OS X 10.9. Apple deprecated GCC a long time ago. Just use Clang, or if you need fortran/openmp/..., install GCC yourself through homebrew/macports/...
来源：https://stackoverflow.com/questions/19535422/os-x-10-9-gcc-links-to-clang