[Cmake] Conditional CMakeLists.txt on CMake version?

[Amitha Perera]

Is there a way to condition CMakeLists.txt on the CMake version? I'd
like to implement some changes to the vxl CMakeLists.txt files to use
some of the 1.3 functionality, without breaking the builds for 1.2
users. Something like
  IF( CMAKE<1.3 )
     do old stuff
  ELSE
     do new stuff
  ENDIF

Thanks,
Amitha.