The nomakedefs stuff for cross-compiling support broke the code to
treat enabling or disabling some optional features as not breaking
save and bones file compatibility. It was relying on a macro whose
definition was local to mdlib.c rather than propagated among files.
makedefs still constructs date.h with a value indicating the ignored
features but the actual compatability check doesn't use that anymore.
Toggling SCORE_ON_BOTL shouldn't have caused existing files to be
rejected but they were.
3806dae153