[native] How to specify a different version of GCC in the same path

Hello,

I was wondering how you can specify which binary a toolchain should use. I have both GCC 4.9.3 and GCC 5.3 installed on my machine. I found that you can specify an install path but not how you can specify the binaries to use.

        toolChains {
            gcc(Gcc) {
                // /usr/bin/g++-4.9
            }
            gcc5(Gcc) {
                // /usr/bin/g++-5
            }
            clang(Clang) {
            }
            visualCpp(VisualCpp) {
            }
        }