Bootstrapping from the previous version of clang would be easier. GCC cares so much about portability because the GNU project's goal was to replace the userspac

Bootstrapping from the previous version of clang would be easier. GCC cares so much about portability because the GNU project's goal was to replace the userspace on proprietary Unices, however ancient or quirky. There are few such systems left, and they are not clang's target audience.