grep: mark unused parameter in output function

This is a callback used with grep_options.output, but we don't look at
the grep_opt parameter, as we're just writing the output to stdout.

Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

1 files changed, 1 insertions, 1 deletions

diff --git a/grep.c b/grep.c
index 0904d55b24..0124eb1960 100644
--- a/grep.c
+++ b/grep.c
@@ -17,7 +17,7 @@ static int grep_source_load(struct grep_source *gs);
 static int grep_source_is_binary(struct grep_source *gs,
 				 struct index_state *istate);
 
-static void std_output(struct grep_opt *opt, const void *buf, size_t size)
+static void std_output(struct grep_opt *opt UNUSED, const void *buf, size_t size)
 {
 	fwrite(buf, size, 1, stdout);
 }