(path_concat): Don't access dir[-1] if dir is the empty string.

diff --git a/lib/path-concat.c b/lib/path-concat.c
index 8c4bbb4e8b2e73c3a5b5d16df79ffea1dc1fbda2..d6dafc939850ad1467f2612f88649364313e642a 100644 (file)
--- a/lib/path-concat.c
+++ b/lib/path-concat.c
@@ -86,10 +86,13 @@ path_concat (const char *dir, const char *base, char **base_in_result)
 
   p = mempcpy (p_concat, dir, dir_len);
 
-  if (ISSLASH (*(p - 1)) && ISSLASH(*base))
-    --p;
-  else if (!ISSLASH (*(p - 1)) && !ISSLASH(*base))
-    *p++ = DIRECTORY_SEPARATOR;
+  if (dir_len > 0)
+    {
+      if (ISSLASH (*(p - 1)) && ISSLASH(*base))
+       --p;
+      else if (!ISSLASH (*(p - 1)) && !ISSLASH(*base))
+       *p++ = DIRECTORY_SEPARATOR;
+    }
 
   if (base_in_result)
     *base_in_result = p;