With the Xcode Developer Tools installed, configuring and building
just works. OS X includes OpenSSL and Sqlite3. MySQL and gettext-style
message translation isn't bundled with OS X, and must be installed
seperately. The fink package manager is recommended. It can be
downloaded at http://fink.sourceforge.net/

Once fink is installed, use the 'Fink Commander' application to
install packages, or, from the command line as an administrator, 'sudo
fink install PACKAGE'.

The important packages for Penn:

mysql15-dev      : MySQL
postgresql82-dev : Postgresql
libgettext3-dev  : Message translation.

Answer yes when if asked if you want to install additional packages
that they depend on.

fink installs packages in the /sw tree, which configure does not
normally check. Run it like so for message translation:

% CPPFLAGS=-I/sw/include LDFLAGS=-L/sw/lib ./configure

The database servers will be detected as long as /sw/bin is your path,
which, if you followed the installation istructions for fink,
will. Otherwise, run configure as:

% ./configure --with-mysql=/sw/bin/mysql_config
or
% ./configure --with-postgresql=/sw/bin/pgconfig