very slow icedtea6 builds

[Matthias Klose]

current icedtea6 builds take a loon time (for me, 14h instead of 4h, including
running the jtreg harness). My last build from 2008-06-05 still takes 4h. Andrew
reported a similiar problem on irc. The current repository is fixed, in that it
doesn't build a debug jdk for the stage2 build, but I still see the much
increased build times (e.g. building the rt.jar during the image install takes
more than cpu 120min) on an Athlon64 4400+. Any suggestions what could be the
cause for this? This seems to be consistent across used GCC versions and
architectures.

  Matthias