Log Message:
Upgrade apr-util to version 1.3.8, which, unlike 1.3.7, is still downloadable.

Changes since 1.3.7:
 - Use locally scoped variables in PostgreSQL driver to avoid stomping
   on return codes.
 - Fix race conditions in initialisation of DBD, DBM and DSO.
 - Expose DBM libs in apu-1-config by default. To avoid that, use
   apu-1-config --avoid-dbm --libs. To get just DBM libs, use
   apu-1-config --dbm-libs.
 - Make sure --without-ldap works.