Config files.  If you want to add new programs to the package, put
the source, man page, and any include files in ../extras.  Then add
the program name to the appropriate .lst file in that directory.

The *.bld files are scripts to build the files that depend on these
file lists.  The *.p? files are partial sources that get catted together
with the file lists by the build scripts.  Do not edit the generated
Makefiles.  Do not edit the *.bld or *.p? files.  Do not edit anything
but the *.lst files in the target directory.