Unbreak with newer libc++. FreeBSD r447202

Index: src/3rdparty/squirrel/squirrel/sqvm.cpp
--- src/3rdparty/squirrel/squirrel/sqvm.cpp.orig
+++ src/3rdparty/squirrel/squirrel/sqvm.cpp
@@ -5,9 +5,9 @@
 #include "../../../stdafx.h"
 #include "../../fmt/format.h"
 
+#include <math.h>
 #include <squirrel.h>
 #include "sqpcheader.h"
-#include <math.h>
 #include "sqopcodes.h"
 #include "sqfuncproto.h"
 #include "sqvm.h"
