to open the mounted block device containing the directory to put the bad
sector files in, and opening of mounted block devices hasn't been allowed
since Net/2 or before. Attempt to open the raw device instead. Be more
careful about long names.
Use lstat() instead of stat() to search for block devices so that my
symlink to the default floppy doesn't cause problems.
Check for truncation of the block number when it is squeezed through the
mknod() interface. The maximum used to be only 32767, but now it large
enough.
