Changes include:
- Rename to wmclock.1.
- Use @prefix@ instead of /usr for the location of the language xpm files.
- Hardcode date instead of picking it up from a variable in the Makefile.
This is a feature that was present in the pre-autotools configure script.
Note a syntax change:
./configure --lang foo
is now
./configure --with-lang=foo
Also remove the .xpm files in the root directory, as they are created during
configuration.