* lib/bitset_stats.c (bitset_stats_read, bitset_stats_write):

* lib/bitset_stats.c (bitset_stats_read, bitset_stats_write):
Check for close failures.
* src/files.h (xfclose): Return void, not int, since it always
returned zero.
* src/files.c (xfclose): Likewise.  Report I/O error if ferror
indicates one.
* src/output.c (output_skeleton): Use xfclose rather than fclose
and ferror.  xfclose now checks ferror.

* data/glr.c (YYLEFTMOST_STATE): Remove.
(yyreportTree): Use a stack-based leftmost state.  This avoids
our continuing battles with bogus warnings about initializers.