It seems to install some libraries that depend on /usr/lib/system/libsystem_darwin.dylib, which doesn't exist. Googling suggests it will be there in macOS 10.13, but on Sierra or earlier, you're outta luck.
It looks like the only directly-affected PG dependency is libxml; if you leave out --with-libxml you can still build.
I found this out the hard way on longfin's host, so I've temporarily removed --with-libxml from that animal's configuration to restore it to service. I trust I'll be able to re-enable that after 10.13 comes out.