Improve compiler and flag detection in bazel builds

[devjgm]

In #278 @remyabel suggested the following:

If we're going to support multiple compilers, the script will probably grow larger as we detect the executable and use the appropriate switch/flags. Just spitballing, but what do you think about adopting an approach similar to this? TL;DR, compile a program in Bazel that uses compiler-specific version macros then spits out the information.

@coryan liked this idea, saying

I am starting to like @remyabel's approach, though we are repeating work that CMake does, we are doomed to repeat it to support Bazel.
And if we are detecting the compiler make and model in C++ then I suggest we change as much as we can from build_info.cc.in into a .cc and do the detection once in a lambda. Can be done if a future PR.