* tools/dev/unix-build/Makefile.svn: In my custom build script,
   restore the rpath hacks for serf 1.3, which are still needed
   to get working svn and svnauth binaries on my systems.
   Without these rpath linker flags binaries fail to run because
   libserf cannot be loaded.


git-svn-id: https://svn.apache.org/repos/asf/subversion/trunk@1515976 13f79535-47bb-0310-9956-ffa450edef68