Yes, I did install libpq via brew and I there are files in /usr/local/opt/libpq/include.
I followed this command and then the ones that followed to create the link and to test the link.
brew install ant afflib libewf libpq.
In case you haven’t seen my response on the other thread on this topic…it looks like this is simply a case of the instructions being out of date. The dependency on PostgreSQL was removed in TSK release 4.10.0. You should not need to perform any of the PostgreSQL related steps to build the Sleuthkit Java bindings.