Brew config option to ignore outdated XCode?

Ahoy. I’ve got XCode 10.3 installed in two machines running MacOS Mojave. To me, my configuration is fine, but brew dr warns about outdated XCode directing me to either upgrade to XCode 11 or delete it. (An aside, is this a genuine option?) Cool—thanks Dr. Brew. *ignore*. Now then, when trying to brew upgrade certain formula from HEAD, the build fails for the specific reason that XCode is outdated. Looking at the formula itself, there’s nothing that demands latest or more recent version of XCode, and when I clone the actual tool from github and build manually (using the XCode 10.3 tools), it builds and runs no prob.

Is there a brew config option to set à la HOMEBREW_MAKE_JOBS or similar to inform brew that it is OK to have an older XCode version so that the above won’t happen?