stefan, I have a patch to abuild.sh on the issue tracker. This patch works as follows:
If there is a targets/vendor/mainboard/Config-abuild.lb
that will be used instead of the auto-generated one. See what you think.
See example
targets/digitallogic/msm586seg/Config-abuild.lb

This is how it looks.
 ~/src/LinuxBIOSv2/util/abuild/abuild.sh  -t digitallogic/msm586seg ~/src/LinuxBIOSv2/
Processing mainboard/digitallogic/msm586seg (i386: ok)
Used existing test target /home/rminnich/src/LinuxBIOSv2//targets/digitallogic/msm586seg/Config-abuild.lb
  Creating builddir...ok
  Compiling image ..ok.

The msm586seg now builds correctly in abuild. if this patch is ok, I will apply it or you can.

Also, note that abuild won't create linuxbios-builds if you specify -t ... this is a bug.

ron