[CMake] Update multiple subprojects in CTest script

[Stefan Reuschl]

Hi all,

updating multiple subprojects in a CTest script and record the results to  
show in CDash
is not supported, see: http://public.kitware.com/Bug/view.php?id=8263

My current workaround is to dynamically set svn:externals before the call  
to ctest_update()
which showed the following issues:
- CTest does not yet parse the output of svn update if svn:externals are  
involved, see
   http://public.kitware.com/Bug/view.php?id=12630
- CTest will mark the working copy as modified, which of course is correct  
because of the
   modified svn:externals property, but annoying to look at in CDash.
- works only for svn
Because of that issues I'm looking for a cleaner solution.

The most promising approach I have found so far seems to do multiple calls  
to ctest_update()
and manually merge the resulting Update.xml files as described here:
http://www.cmake.org/pipermail/cmake/2010-March/036001.html
Is that the best way to go or does anyone has better suggestions?

In that mailing list thread CMake authors also noted that native support  
in CTest
can't be expected any time soon because the CDash database doesn't support  
recording updates
 from different repositories. Is that still true?

Regards,
   Stefan