root-config has new options --arch and --has-<feature> where feature can be

any of the ./configure --has-<features>, e.g. root-config --has-mysql
returns "yes" if mysql was enabled during the ROOT installation and
"no" otherwise. By Christian Holm.


git-svn-id: http://root.cern.ch/svn/root/trunk@4222 27541ba8-7e3a-0410-8455-c3a389f83636