diff --git a/src/d_main.c b/src/d_main.c
index f67731bb..9239f191 100644
--- a/src/d_main.c
+++ b/src/d_main.c
@@ -743,7 +743,7 @@ static void LoadBaseFile(void)
 
         if (d.dir && d.func)
         {
-            char *s = M_StringJoin(d.func(), DIR_SEPARATOR_S, d.dir, NULL);
+            char *s = M_StringJoin(d.func(), DIR_SEPARATOR_S, d.dir);
             result = W_InitBaseFile(s);
             free(s);
         }
diff --git a/src/w_wad.c b/src/w_wad.c
index 0446d98a..08797aa4 100644
--- a/src/w_wad.c
+++ b/src/w_wad.c
@@ -399,7 +399,7 @@ static w_handle_t base_handle;
 boolean W_InitBaseFile(const char *path)
 {
     char *filename =
-        M_StringJoin(path, DIR_SEPARATOR_S, PROJECT_SHORTNAME ".pk3", NULL);
+        M_StringJoin(path, DIR_SEPARATOR_S, PROJECT_SHORTNAME ".pk3");
 
     w_type_t result = w_zip_module.Open(filename, &base_handle);