Verify that the compilers supposed to be used actually work

[ocaisa]

On generoso, we had an NFS issue which meant that some permissions got corrupted. The end result was that gcc was not resolving to the GCCcore module (which was now unexecutable) but to the system gcc. This slips through unnoticed because we do not use full paths to $CC and friends (and sometimes for good reasons, like for our rpath wrappers). gcc in particular is a problem case since it is (almost) certain to exist on the system.

We should add a check to ensure that version of the compilers in our path match the versions we expect them to be. Example commands to achieve this:

gcc -dumpfullversion -dumpversion
clang -dumpversion
icc -dumpversion  # Does not give a version that matches the module file
icx -dumpversion  # Does not give a version that matches the module file