run_command() was only run at configure time, meaning the generated
version (that was passed on to the sources via -DFUZZEL_VERSION)
became stale.
Fix by implementing a shell script that generates a header file, and
wrap this in a custom target that is run every time (but the generated
file is only updated when the version changes)
This makes -f,--font behave just like the configuration file option
'font'; the first font in the list is the primary font, and the
remaining fonts are fallback fonts used when a glyph cannot be found
in the primary font.
They where previously identical to the corresponding 'regular'
colors. Now, we've done a saturated add with 0x202020 (which seems to
be roughly the difference between the other regular and bright
colors).
