// #defines that gcc encountered while processing the input
// and its included files.
func (p *Package) gccDefines(stdin []byte) string {
	base := append(gccBaseCmd, "-E", "-dM", "-xc")
	base = append(base, p.gccMachine()...)
	stdout, _ := runGcc(stdin, append(append(base, p.GccOptions...), "-"))
	return stdout
}

// gccErrors runs gcc over the C program stdin and returns