kbuild: scripts/kconfig/Makefile cleanup and fixes

This patch set:
Changes the update-po-config target to work when make is run from KBUILD_OUTDIR.
Changes the update-po-config target to reflect the new layout of arch/um. Adds a check to only build kxgettext when needed.
Changes the qconf and gconf targets to change hostprogs-y when they are being built like nconf and mconf instead of defining *-objs. Cleans up the clean-files definitions.
Silences comands unless V=1.

I've also attached the patches as requested by Michal Marek.

Thanks,

Peter

That worked, thanks. Pushed to kbuild-2.6.git#kconfig.

Michal