This reverts commit 85b468262e "Remove unused liblockdep packaging"
and 87d08943da "liblockdep: Stop trying to build packages, as it
failed to build again", but doesn't restore the patches. All our
patches, and further build fixes, were applied upstream as of
v4.13-rc1.
By passing both -C and -f options to make, we can separate makefiles
from the output directory without adding prefixes to all targets.
We can also reduce the 'clean' commands to little more than 'rm -rf'.
Ben Hutchings
Hilko Bengen