These instructions will guide you how to get a complete build environment
for showtime. The envionment will not depend on MacPorts, except for pkg-config.

Create a new directory with the name of your choice. Then donwload and
extract packages for these projects into it:

libav, http:https://libav.org/ (at least 0.7)
freetype, http:https://www.freetype.org

Now copy the buildenv* scripts to the new directory.

There are several script for building different envionments
buildenv.10.4-i386.sh, 10.4 SDK, gcc 4.0, i386
buildenv.10.6-i386.sh, 10.6 SDK, gcc 4.2, i386
... and others ...
buildenv.common.sh is a common help script used by all build scripts.

After you have copied the files you may want to change the INSTALLDIR
variable in buildenv.common.sh before running them.

When done run for example:
$ sh buildenv.10.6-i386.sh

Now you can compile showtime using:

./configure --cc="gcc-4.0 -arch i386" --macosx-sdk=/Developer/SDKs/MacOSX10.4u.sdk --pkg-config-dir=$HOME/showtime-env-10.4-i386/lib/pkgconfig 

Make sure to use same gcc version and SDK when building showtime.