This directory holds git checkouts of any additional software.
You can automatically populate it with /medianet/sbin/mn_checkout, and build
all components in one go with /medianet/sbin/mn_build. Individual components
can be fetched and built by adding the package name.

To include a new custom component FOO, you need to write two little modules:
custom_builds/FOO.checkout, which fetches the software, and 
custom_builds/FOO.build, which builds it with all necessary fixes and
compiler flags, and installs it to $DESTDIR.
 
These modules contain shell commands, but need not be executable, as they are
included ("sourced") by the master script. Checkout modules execute with 
custom_builds/ as their current working directory. Build modules execute in
the respective source directory.