utf8.h: squelch unused-parameter warnings with NO_ICONV

Since DEVELOPER=YesPlease build enables -Wunused-parameter warnings
these days, the fallback definition for reencode_string_len() that
did not touch any of its parameters but one needs to be annotated
properly.

Signed-off-by: Mike Hommey <mh@glandium.org>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

Author: glandium

utf8.h

@@ -33,8 +33,9 @@ char *reencode_string_len(const char *in, size_t insz,
 			  const char *in_encoding,
 			  size_t *outsz);
 #else
-static inline char *reencode_string_len(const char *a, size_t b,
-					const char *c, const char *d, size_t *e)
+static inline char *reencode_string_len(const char *a UNUSED, size_t b UNUSED,
+					const char *c UNUSED,
+					const char *d UNUSED, size_t *e)
 { if (e) *e = 0; return NULL; }
 #endif