当我进入
brew install gcc49
我明白了：
Warning: gcc49-4.9.0 already installed
当我用gcc -v
Configured with: --prefix=/Applications/Xcode.app/Contents/Developer/usr --with-gxx-include-dir=/usr/include/c++/4.2.1
Apple LLVM version 5.1 (clang-503.0.38) (based on LLVM 3.4svn)
Target: x86_64-apple-darwin12.5.0
Thread model: posix
除了通过自制软件安装gcc49以便能够使用它还有什么我需要做的吗？