Include wx/math.h according to precompiled headers of wx/wx.h (with other minor cleaning).

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@39745 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775

src/gtk1/spinbutt.cpp

@@ -17,9 +17,9 @@
 
 #ifndef WX_PRECOMP
     #include "wx/utils.h"
+    #include "wx/math.h"
 #endif
 
-#include "wx/math.h"
 #include "wx/gtk1/private.h"
 
 //-----------------------------------------------------------------------------