nicer comments in the generated files.
	-import_runtime_cgo
		If set (which it is by default) import runtime/cgo in
		generated output.
	-import_syscall
		If set (which it is by default) import syscall in
		generated output.
	-gccgo
		Generate output for the gccgo compiler rather than the
		gc compiler.
	-gccgoprefix prefix
		The -fgo-prefix option to be used with gccgo.