Ah, there's more info in https://github.com/hpcugent/easybuild-easyconfigs/pull/701 .

So, `GCC` is a dependency for `mcc`, makes sense. 
You're stating that GCC 4.4.x or higher is required, so add a hard version check for > 4.4 in the easyblock?

Also, check whether `mcc` is available (there's a `which` Python function available in `easybuild.tools.systemtools`)?