mingw: fix the shortlog --output=<file> test

diff --git a/setup.c b/setup.c
index 1563cd42df2865d9f4390c9e68cdc666b45fcf96..c86bf5c9fabeab4b60b0696b9ae9b2f0f2bb720e 100644 (file)
--- a/setup.c
+++ b/setup.c
@@ -102,7 +102,7 @@ char *prefix_path_gently(const char *prefix, int len,
                        return NULL;
                }
        } else {
-               sanitized = xstrfmt("%.*s%s", len, prefix, path);
+               sanitized = xstrfmt("%.*s%s", len, len ? prefix : "", path);
                if (remaining_prefix)
                        *remaining_prefix = len;
                if (normalize_path_copy_len(sanitized, sanitized, remaining_prefix)) {