testing: Switch to Debian based guest images

Instead of extracting a downloaded Gentoo filesystem tree into a file
containing a reiserfs filesystem, create an ext3 filesystem inside a
sparse file, mount it and debootstrap an up-to-date Debian system. Use
this image as base for all UML guest images.

Also, drop support for the various consoles and use xterm
unconditionally.

testing/scripts/build-umlkernel

@@ -67,15 +67,6 @@ fi
 cecho " * Changing to directory '$BUILDDIR'"
 cd $BUILDDIR
 
-LOGFILE=${BUILDDIR}/testing.log
-
-if [ ! -f $LOGFILE ]
-then
-    cecho-n " * Logfile '$LOGFILE' does not exist..creating.."
-    touch $LOGFILE
-    cgecho "done"
-fi
-
 cecho-n " * Unpacking kernel.."
 tar xjf $KERNEL >> $LOGFILE 2>&1
 cgecho "done"
@@ -119,10 +110,10 @@ cp $KERNELCONFIG .config
 cecho "!!"
 cecho "!! Making .config for kernel. You might be prompted for new parameters!"
 cecho "!!"
-make oldconfig ARCH=um SUBARCH=i386 2>&1 | tee -a $LOGFILE
+make oldconfig ARCH=um 2>&1 | tee -a $LOGFILE
 
 cecho-n " * Now compiling uml kernel.."
-make linux ARCH=um SUBARCH=i386 >> $LOGFILE 2>&1
+make -j5 linux ARCH=um >> $LOGFILE 2>&1
 cgecho "done"
 
 cecho-n " * Copying uml kernel to '${BUILDDIR}/linux-uml-${KERNELVERSION}'.."