return strings.HasPrefix(t, k+"_")
	})
}

// rewriteCalls rewrites all calls that pass pointers to check that
// they follow the rules for passing pointers between Go and C.
// This reports whether the package needs to import unsafe as _cgo_unsafe.
func (p *Package) rewriteCalls(f *File) bool {
	needsUnsafe := false
	// Walk backward so that in C.f1(C.f2()) we rewrite C.f2 first.