Don't use malloc.h header on OpenBSD.

--- win/Qt/qt_win.cpp.orig	Thu Nov 20 22:02:50 2014
+++ win/Qt/qt_win.cpp	Thu Nov 20 22:13:01 2014
@@ -104,8 +104,6 @@ extern "C" {
 #include <dirent.h>
 #ifdef Q_WS_MACX
 #  include <sys/malloc.h>
-#else
-#  include <malloc.h>
 #endif
 
 #ifdef _WS_X11_
