several extensive changes in configure and in several Module.mk's:

  - automatic architecture detection (first architecture argument
    only needed if non-default compiler is required)
  - better detection and avoidance of duplicate libraries for the
    authentication modules (afs, krb5 and srp modules can be build
    at the same time)
Mods by Christian Holm and me.


git-svn-id: http://root.cern.ch/svn/root/trunk@7197 27541ba8-7e3a-0410-8455-c3a389f83636