Prepare for 0.172.

Prepare for 0.172.

It has been only 10 days since the previous release and there are
no functional changes compared to 0.171. The speedup of eu-readelf -N
is pretty nice. And ~25 patches fix various bugs (hangs and crashes)
in dealing with bad DWARF5 data. Most have been found by running the
afl fuzzer on eu-readelf and various testcases.

Signed-off-by: Mark Wielaard <mark@klomp.org>