dlb capacity (trunk only)

dlb capacity (trunk only)

     From the newsgroup:  if someone adds too many new special levels, dlb
creation during install will give a warning but still exit with success,
and the subsequent installation won't know that the excess files need to be
placed in the playground separately.  The result is that some files will
be missing when nethack tries to access them.  The newsgroup thread states
that slash'em increased dlb's default limit of 200 files to 300, and the
unnethack variant increased it to 250 and also changed the overflow message
into an error that causes 'make' to quit.  (The thread was initiated by
someone working on his own, not affiliated with either variant, who asked
for help figuring out why nethack couldn't find files at the end of the
alphabet.  My answer didn't help much; I thought he was working with
separate files rather than with a DLB container.)

     I started to go with the too-many-files-is-an-error fix, but instead
went the GNU route ("no arbitrary limits") and made the number of allowed
files become dynamic.  It starts at 200 and expands by increments of 40
when necessary.