cLanguageVersion applies to old clang-cl compiler

Scenario

• Make a profile with clang-cl 10.0 and vcvars from MSVC 14.2;
• Set "cpp.cLanguageVersion:c11" in your product.

Expected behavior
qbs doesn't set "/std:c11" as a compiler flag because clang-cl 10.0 doesn't support it

Actual behavior
qbs set "/std:c11", clang-cl raises "unused-command-line-argument" warning

Additional info
It looks like comparing MSVC and clang-cl versions via Utilities.versionCompare works errorneously because of the "compiler version build number" component in cpp.compilerVersion for MSVC