Fix build on OpenBSD by reverting r958263. According to the GNU ld documentation, there are systems where undefined references in shared libraries are normal. So disallowing them by default on all platforms is wrong. Please only enable this by default on platforms that are known to have no issues with it.
Fix build on OpenBSD by reverting r958263.
According to the GNU ld documentation, there are systems where undefined
references in shared libraries are normal. So disallowing them by default
on all platforms is wrong. Please only enable this by default on platforms
that are known to have no issues with it.

jmckaskill/subversion,jmckaskill/subversion,jmckaskill/subversion,jmckaskill/subversion,jmckaskill/subversion,jmckaskill/subversion,jmckaskill/subversion,jmckaskill/subversion