Is there any further thoughts on this ITS? It's still open and it doesn't look like the patch has been applied, but it seemed like we'd reached a conclusion that it was the right thing to do.
To recap, the problem is that libldap_r isn't being linked with the threading libraries, which means that when the linker builds the shared library, it doesn't have symbol versioning information available for the pthread functions and creates unversioned references. If the current ABI of the functions ever changes (as has happened in the past with glibc on Alpha), segfaults and other unpleasantness result.
The patch adds the threading libraries to the link command for libldap_r so that the linker has the symbol versioning information available and can bind the pthread functions to the appropriate symbol versions in glibc, allowing the library to keep working using glibc's backwards compatibility support even if the current ABI changes again.