The main Portfile to build with macports is included here. There has
become a little post processing step and the make-package.sh simply
uses the create-osx-app-bundle.sh script to create an app.zip file
from the macports built sources.

As of January 2015, the build is performed using the following script
sequence. The create-osx-app-bundle.sh script will create
~/FontForge.app.dmg which you can then archive and upload that
file as desired. The script which does the upload is not in this
repository as it includes some authentication credentials and is
specific to the current distribution site.

Before this starts, change to the directory
/usr/local/src/github-fontforge
and clone the fontforge sources into there.
Add the aforementioned path to /opt/local/etc/macports/sources.conf as
file:///usr/local/src/github-fontforge
above the default MacPorts sources.

portindex
cd fontforge/osx
./force-rebuild.sh
cd /opt/local/var/macports/build/_usr_local_src_github-fontforge_fontforge_osx/
bash ./osx/create-osx-app-bundle.sh

As you can see in the post-extract of the Portfile a copy of gnulib is
also expected to be found at /usr/local/src/github-fontforge/gnulib.
This is not strictly needed and you can modify the Portfile to avoid
it but having a reliance on that local copy means much less network
traffic and thus is useful for repeated builds.

You will also want to configure your macports environment to include
in binaries so that the link paths can be modified for packaged
execution.

For example, the file
/opt/local/share/macports/Tcl/port1.0/portconfigure.tcl default
configure.ldflags {"-L${prefix}/lib -Wl,-headerpad_max_install_names"}