Fallback to pkg-config when libpq is not found with CMake.

[skasperski]

Hi,

I think CMake support for libpq is quite new and not available on all systems. It might become obsolete at some point, but for now it might be desirable to offer a fallback for finding libpq with pkg-config, which should be available on many systems.

I am not exactly sure why a policy is required for PostgreSQL, so I moved the new stuff to a separate block.

Best regards,
Sebastian

[jtv]

I think CMake support for libpq is quite new and not available on all systems. It might become obsolete at some point, but for now it might be desirable to offer a fallback for finding libpq with pkg-config, which should be available on many systems.

Thank you! Yes, some people experience problems finding PostgreSQL when building with CMake, so it'd be great if this solves it.

I am not exactly sure why a policy is required for PostgreSQL, so I moved the new stuff to a separate block.

Could it be because libpqxx also requires the libpq-fe.h header? On Debian I believe that header is in the postgresql-dev package, not in the libpq-dev package.

[skasperski]

Could it be because libpqxx also requires the libpq-fe.h header? On Debian I believe that header is in the postgresql-dev package, not in the libpq-dev package.

I think it should not matter where it is, pkg-config should give the location via include-dir. I used to include the libpq-fe.h and don't recall any issue, at least not on Ubuntu.

[jtv]

And thank you once again.