Prevent the use of windowsx.h with Wine source.

[Robert Shearman]

Mike McCormack wrote:

>+#ifdef __WINESRC__
>+/* This file contains macros that cause warnings on gcc 4.1, so avoid it. */
>+#error Please avoid use of windowsx.h in Wine source code.
>+#endif
>+ 
>

Why don't we fix the macros as suggested by Francois, rather than
preventing its use? It seems like a big waste of time to have submitted
all of the patches to the files using windowsx.h when fixing the macros
is necessary for Winelib anyway.

-- 
Rob Shearman