[GCC-XML] Unknown CMake command "ELSEIF"

[Brad King]

Mathieu Malaterre wrote:
> Brad,
> 
>   Could you change the minimum requirement to 2.4.5
> 
> CMAKE_MINIMUM_REQUIRED(VERSION 2.4.5)

Done.  There was already this check with the FATAL_ERROR option in the
GCC_XML subdirectory.  However the reported problem happens in the GCC
subdirectory which is checked first.  I put a check at the top.

-Brad