builtins: print setup info if repo is found

Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

cache.h

@@ -1062,6 +1062,7 @@ __attribute__((format (printf, 1, 2)))
 extern void trace_printf(const char *format, ...);
 __attribute__((format (printf, 2, 3)))
 extern void trace_argv_printf(const char **argv, const char *format, ...);
+extern void trace_repo_setup(const char *prefix);
 
 /* convert.c */
 /* returns 1 if *dst was used */