* as.h (flag_*): Added comments describing meanings of some of these variables.

* as.h (flag_*): Added comments describing meanings of some of these variables.
(struct frag): Add some comments about the ns32k-specific fields and why
they're here.
(SIZEOF_STRUCT_FRAG): Cast addresses to char*, not int.
(flag_print_statistics): Declare.

* as.c (parse_args): Set flag_print_statistics instead of statistics_flag.
Options array is now const.  Added new option "dump-config"; if specified,
print TARGET_ALIAS, TARGET_CANONICAL, TARGET_CPU, TARGET_OBJ_FORMAT, and
TARGET_FORMAT, if defined.
(main): Change test to check flag_print_statistics.
(statistics_flag): Deleted.