if a1.Mode == "preprocess PGO profile" {
			fmt.Fprintf(h, "pgofile %s\n", b.fileHash(a1.built))
		}
	}

	return h.Sum()
}

// needCgoHdr reports whether the actions triggered by this one
// expect to be able to access the cgo-generated header file.
func (b *Builder) needCgoHdr(a *Action) bool {
	// If this build triggers a header install, run cgo to get the header.