Merge branch 'cb/maint-1.6.3-grep-relative-up' into maint

* cb/maint-1.6.3-grep-relative-up:
  grep: accept relative paths outside current working directory
  grep: fix exit status if external_grep() punts

Conflicts:
	t/t7002-grep.sh

grep.h

@@ -59,6 +59,7 @@ struct grep_opt {
 	struct grep_pat *pattern_list;
 	struct grep_pat **pattern_tail;
 	struct grep_expr *pattern_expression;
+	const char *prefix;
 	int prefix_length;
 	regex_t regexp;
 	int linenum;