Add a bit more explanations on the meaning of OBSOLETE and EXPERIMENTAL.

-------- diffstat follows --------
/trunk/config/global/ct-behave.in | 22 13 9 0 +++++++++++++---------
/trunk/docs/overview.txt | 8 6 2 0 ++++++--
2 files changed, 19 insertions(+), 11 deletions(-)

 # powerpc specific configuration file

 config ARCH_powerpc

     select ARCH_SUPPORT_ABI

     select ARCH_SUPPORT_CPU

     select ARCH_SUPPORT_TUNE

     help

       The PowerPC architecture, as defined by:

         http://www.ibm.com/developerworks/eserver/articles/archguide.html