[CMake] FinXXX.cmake messages

[Bill Hoffman]

Andreas Schneider wrote:
> Hi,
>
> we get some mails on the wengophone mailing list like.
>
>
> 	While building using Cmake I get following error:
>
> 	CMake Error: Could not find XML2
>
> 	Any ideas how to fix this?
>
>
> So in the FindXXX.cmake file for
>
>      if (XML2_FIND_REQUIRED)
>        message(FATAL_ERROR "Could not find XML2")
>      endif (XML2_FIND_REQUIRED)
>
> we should rather use something like "Please install the XML2 library and
> development tools" for Lusers. Maybe this avoids some dumb questions.
>   
Don't use the required flag for the find model, but after you find it, 
then print your own fatal error message that says what ever you want. 

-Bill