Add a patch for adding open/read/write/close/setmode aliases to the arm msvcrt

This requires using llvm-dlltool, since genlib currently doesn't
support aliases.

patches/mingw-0004.patch

@@ -0,0 +1,25 @@
+From cf2434c417310703cfda61943c66f33fa23bde57 Mon Sep 17 00:00:00 2001
+From: =?UTF-8?q?Martin=20Storsj=C3=B6?= <martin@martin.st>
+Date: Thu, 18 Aug 2016 09:48:29 +0300
+Subject: [PATCH] Add aliases for open/read/write/close and setmode
+
+---
+ mingw-w64-crt/libarm32/msvcrt.def | 5 +++++
+ 1 file changed, 5 insertions(+)
+
+diff --git a/mingw-w64-crt/libarm32/msvcrt.def b/mingw-w64-crt/libarm32/msvcrt.def
+index 2533d5a..4e3fe25 100644
+--- a/mingw-w64-crt/libarm32/msvcrt.def
++++ b/mingw-w64-crt/libarm32/msvcrt.def
+@@ -1278,3 +1278,8 @@ wprintf
+ wprintf_s
+ wscanf
+ wscanf_s
++open = _open
++read = _read
++write = _write
++close = _close
++setmode = _setmode
+-- 
+2.7.4
+