Allow installation to proceed when CLT is dispersed

@benhoskings commit message should say it all. mind cutting a release with this?
I get what you're saying, but it is working as I intend. I consider the dep unmet in this situation, because one of the binaries has been bait n' switched :)

If you use the homebrew gcc along with the other binaries in the xcode tools suite you're probably in for a bad surprise at some point. The check is there to prevent that surprise.

Perhaps the wording of the message is off. In any case, the intention isn't to say "yes, this is met"; it's to say "yes, attempt to meet it".