From Pere:

For ROOT's Makefile we have intentionally disentangled CINT and dictionaries
by using order dependencies: when CINT gets changed, none of the dictionaries
get rebuilt, unless cint/cint/inc/cintdictversion.h is touched. This allows us
to maintain CINT without pain from the build system - in almost 100% of all
cases the dictionaries are unchanged after patching CINT. The difference is
drastic: 8 seconds (Makefile) compared to more than 5 minutes (CMake).

This change apply the technique to CMake. It still re-links all the libraries since
they depend on libCint.so but the time has been reduced from 7-8 minutes to
about 14 seconds on my Mac.


git-svn-id: http://root.cern.ch/svn/root/trunk@42930 27541ba8-7e3a-0410-8455-c3a389f83636