Investigate possible compilation time improvement by compiling gcc and clang from source

When compiling the compilers we can do two things that should improve compilation time:
1. We can set arch parameter to match architecture we are using.

2. We can use profile-guided optimization to optimize compilers to specifically build mongodb. This is done by first compiling the compilers with -fprofile-generate, compiling mongodb to collect the profile and later re-compiling the compilers with optimizations, based on the collected profile with -fprofile-use.