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(-)

# x86_64 specific options

config ARCH_x86_64

    select ARCH_64

    select ARCH_SUPPORT_ARCH

    select ARCH_SUPPORT_CPU

    select ARCH_SUPPORT_TUNE

    help

      The x86_64 architecture, as defined by:

        http://www.amd.com/us-en/Processors/DevelopWithAMD/0,,30_2252_875_7044,00.html