Support pkg-config builds

[tbussmann]

We currently support building extensions and compiling against the libraries of PostgresApp by providing a working pg_config. However there is a second supported way using pkg-config, however we do exclude the $(PREFIX)/lib/pkgconfig folder during packaging in CopyBinaries.sh. Would it make sense to include that? Users could than run pkg-config-based builds with PKG_CONFIG_PATH=/Applications/Postgres.app/Contents/Versions/latest/lib/pkgconfig against PostgresApp.

[jakob]

This sounds like a good idea. Could adding those files break anything? If not, we could probably include them with the next scheduled release (Feb 13)

[jakob]

I forgot about this, but I do want to follow up on this.

Should we include all pkg-config for all libraries that we ship, or just for some of them? We also include things like OpenSSL. Do we want other software to link to our OpenSSL? Or should we just include the pkg-config file for libpq?