// If the command exits with a non-zero exit status, runGcc prints
// details about what was run and exits.
// Otherwise runGcc returns the data written to standard output and standard error.
// Note that for some of the uses we expect useful data back
// on standard error, but for those uses gcc must still exit 0.
func runGcc(stdin []byte, args []string) (string, string) {

			if window > len(b[i:]) {
				window = len(b[i:])
			}
			// Fill the window with non-match
			for j := 0; j < window; j++ {
				b[i+j] = byte(100)
			}
			// Try to find something that doesn't exist
			p := Count(b[i:i+window], []byte{0})
			if p != 0 {
				t.Errorf("TestCountByteNoMatch(%q, 0) = %d", b[i:i+window], p)
			}
			for j := 0; j < window; j++ {
				b[i+j] = byte(0)
			}
		}
	}
}