Fix PCH-less build

Add missing includes for compiling without WX_PRECOMP.

src/common/wincmn.cpp

@@ -47,6 +47,7 @@
     #include "wx/layout.h"
     #include "wx/sizer.h"
     #include "wx/menu.h"
+    #include "wx/button.h"
 #endif //WX_PRECOMP
 
 #if wxUSE_DRAG_AND_DROP

src/msw/debughlp.cpp

@@ -21,6 +21,10 @@
     #pragma hdrstop
 #endif
 
+#ifndef WX_PRECOMP
+    #include "wx/wxcrt.h"
+#endif // WX_PRECOMP
+
 #include "wx/msw/debughlp.h"
 
 #if wxUSE_DBGHELP && wxUSE_DYNLIB_CLASS