panic("not reached")
}

// gccDefines runs gcc -E -dM -xc - over the C program stdin
// and returns the corresponding standard output, which is the
// #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")