clone: replace strcmp by fspathcmp

Replace the use of strcmp by fspathcmp at copy_or_link_directory, which
is more permissive/friendly to case-insensitive file systems.

Suggested-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com>
Signed-off-by: Matheus Tavares <matheus.bernardino@usp.br>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

builtin/clone.c

@@ -441,7 +441,7 @@ static void copy_or_link_directory(struct strbuf *src, struct strbuf *dest,
 		}
 
 		/* Files that cannot be copied bit-for-bit... */
-		if (!strcmp(iter->relative_path, "info/alternates")) {
+		if (!fspathcmp(iter->relative_path, "info/alternates")) {
 			copy_alternates(src, src_repo);
 			continue;
 		}