That suggestion is not really practical as you need to make the same requirement from all your third party libraries. While gcc will spend more time optimizing than go, the main reason for the speed difference at the moment IS unnecessary work done by the preprocessor because of the primitive importing.
No, it's not, unless you count time spent compiling inlined functions and templates as "preprocessing time" (which it isn't—it's compilation time). Time the difference between clang++ on -O0 versus -O3 if you don't believe me.
