grep: accept relative paths outside current working directory

"git grep" would barf at relative paths pointing outside the current
working directory (or subdirectories thereof). Use quote_path_relative(),
which can handle such cases just fine.

[jc: added tests.]

Signed-off-by: Clemens Buchacher <drizzd@aon.at>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

1 files changed, 1 insertions, 0 deletions

diff --git a/grep.h b/grep.h
index a67005de62..5b767c931c 100644
--- a/grep.h
+++ b/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;
 	unsigned linenum:1;