Add pg_config libdir to the library's rpath

[gtzampanakis]

Close #1356.

[gtzampanakis]

NOTE: I have tested this only on centos.

[gtzampanakis]

Looks like rpath is not supported on windows and it failed the build. I just pushed 99262a2 which runs the fix only on Linux.

[gtzampanakis]

Will this be merged?

[dvarrazzo]

Hi, sorry, I thought you still had issues to solve around it.

This changeset makes me pretty nervous because it has just no test. Is there a way to reproduce the issue in first place and then to verify it's fixed by this change?

Can you comment in the setup.py why are we doing that thing?

Can you run a packaging task to verify that build works on all the platforms supported?

Thank you

[zyv]

@gtzampanakis you should need to add the library path to rpath only if it's a dynamic library and the path to it is not already on the default linker path.

There are valid uses for rpath, but in this case you are 99% working around a broken installation of libpq, and unconditionally polluting rpath field for all users of the library.

One could do that conditionally by e.g. checking the output of ldd, but even this would be kind of questionable, because the problem shouldn't be there in the first place...