* src/options.h (struct option_table_struct): set_flags is void*.
* src/options.c (longopts): Support `--output' and `%output'.
(usage): Adjust.
* src/lex.h (tok_setopt): Remove, replaced with...
(tok_intopt, tok_stropt): these new guys.
* src/lex.c (getopt.h): Not needed.
(token_buffer, unlexed_token_buffer): Not const.
(percent_table): Promote `-' over `_' in directive names.
Active `%name-prefix', `file-prefix', and `output'.
(parse_percent_token): Accept possible arguments to directives.
Promote `-' over `_' in directive names.