configure needs to verify some minimal compiler/tools versions.

gcc --version
xcodebuild -version
CC -V

Or at least the more critical ones. Probably should be fatal if it falls below some minimal setting.

Maybe with some setting it needs to be strict and a fatal if it is not exactly matching? So that RE builds could set some option to say "it MUST be the right versions".???

Some thought needs to be put into it. Open builds need to be more flexible, allowing some variety, but the official Oracle shipped builds need to be more strictly checked?