From David Callu, "ust a simple IF ENDIF mismatch in last commit (I use git so no available SVN commit number ) :

CMake Warning (dev) in CMakeLists.txt:
  A logical block opening on the line

    /home/ledocc/work/perso/osg_Workspace/osg/CMakeLists.txt:823 (IF)

  closes on the line

    /home/ledocc/work/perso/osg_Workspace/osg/CMakeLists.txt:893 (ENDIF)

  with mis-matching arguments.

I remove ENDIF argument, it is no longer needed by cmake"