Note:

This is a cross-repository commit, because this highly glibc specific
config.cache file will be put into package/*/glibc/share/config.cache!

Anyway it is highly unlikely that anyone will use OpenSDE to build a system
for those vintage-style CPU models.

Note:

This options are available when "generic" optimization is selected!

This architecture can be considered pretty dead

https://en.wikipedia.org/wiki/DEC_Alpha
.............................................................................
On June 25, 2001, Compaq announced that Alpha would be phased out by 2004 in
favor of Intel's Itanium, canceled the planned EV8 chip, and sold all Alpha
intellectual property to Intel.
.............................................................................

- The formely pattern used $pkg-$ver, which turned out to be
  a bit too strict.

- After finishing the first buildloop we have to go back to
  toplevel srcdir
- This commit also changes the priority of the preconf hook we
  use while building multilib.

  Warning:
  The change of the priority is very sensitive, so you should
  just change it if you really know what you are doing!

- To be able to build "pure" x86-64 systems (non-multilib) we need to remove
  this hardwired multilib by default behavior from the x86-64 architecture
  configuration.

Note:
From now on we do not rely on the glibc32 package anymore by using a second
buildloop while building a 64bit multilib target.