Merge branch 'es/retire-efgrep'

Prepare for GNU [ef]grep that throw warning of their uses.

* es/retire-efgrep:
  check-non-portable-shell: detect obsolescent egrep/fgrep

Author: gitster

t/check-non-portable-shell.pl

@@ -45,6 +45,7 @@ sub err {
 	/\bhead\s+-c\b/ and err 'head -c is not portable (use test_copy_bytes BYTES <file >out)';
 	/(?:\$\(seq|^\s*seq\b)/ and err 'seq is not portable (use test_seq)';
 	/\bgrep\b.*--file\b/ and err 'grep --file FILE is not portable (use grep -f FILE)';
+	/\b[ef]grep\b/ and err 'egrep/fgrep obsolescent (use grep -E/-F)';
 	/\bexport\s+[A-Za-z0-9_]*=/ and err '"export FOO=bar" is not portable (use FOO=bar && export FOO)';
 	/^\s*([A-Z0-9_]+=(\w*|(["']).*?\3)\s+)+(\w+)/ and exists($func{$4}) and
 		err '"FOO=bar shell_func" assignment extends beyond "shell_func"';