Allow easy usage of different compiler versions in the buildsystem

[simonsan]

Right now we can not easily set a compile and a version within our configure script. #1250 did a small fix for clang-9 and clang-10 because we needed that for the CI. But it would be nice to create some parser that "respects the versions making it easier to test for multiple compiler versions" (@TheJJ ).

Regarding:

This should be just a small fix, we should probably implement something that splits compiler into compiler-name and compiler-version => if it's clang and then append the version to clang++.

Originally posted by @simonsan in https://github.com/SFTtech/openage/pull/1250

And yes, the compiler-name-and-version parser would be the real fix. But, if we implement it, the version should actually be respected, since that way you may test multiple compiler versions easily.

Originally posted by @TheJJ in https://github.com/SFTtech/openage/pull/1250

[TheJJ]

To clarify this a bit: we support compiler kind switching (clang, gcc, ...) already, but we don't support switching versions of them (gcc-9, gcc-10). The switching we introduced to allow "easier" debugging of compiler errors (different compilers show errors of varying helpfulness).

So this is about our ./configure script encoding the major compiler version in the output path.