I turned on clang for everything today. It seems to compile big ports like Firefox (even with optimizations turned on), gtk, and Qt just fine. With its faster compilation speed it would be more than worthy for ports.
My guess is that there are very few ports that require gcc specifically and these can easily be made to depend on a gcc port.
My guess is that there are very few ports that require gcc specifically and these can easily be made to depend on a gcc port.