MinGW: Add missing file mode bit defines

diff --git a/RelNotes b/RelNotes
index 028ad79e1f7226088102667085ca5ceb43c4d442..b942e499449d97aeb50c73ca2bdc1c6e6d528743 120000 (symlink)
--- a/RelNotes
+++ b/RelNotes
@@ -1 +1 @@
-Documentation/RelNotes-1.7.2.2.txt
\ No newline at end of file
+Documentation/RelNotes/1.7.4.txt
\ No newline at end of file