Prototype support of %lex-param and %parse-param.

Prototype support of %lex-param and %parse-param.
* src/parse-gram.y: Add the definition of the %lex-param and
%parse-param tokens, plus their rules.
Drop the `_' version of %glr-parser.
Add the "," token.
* src/scan-gram.l (INITIAL): Scan them.
* src/muscle_tab.c: Comment changes.
(muscle_insert, muscle_find): Rename `pair' as `probe'.
* src/muscle_tab.h (MUSCLE_INSERT_PREFIX): Remove unused.
(muscle_entry_s): The `value' member is no longer const.
Adjust all dependencies.
* src/muscle_tab.c (muscle_init): Adjust: use
MUSCLE_INSERT_STRING.
Initialize the obstack earlier.
* src/muscle_tab.h, src/muscle_tab.c (muscle_grow)
(muscle_pair_list_grow): New.
* data/c.m4 (b4_c_function_call, b4_c_args): New.
* data/yacc.c (YYLEX): Use b4_c_function_call to honor %lex-param.
* tests/calc.at: Use %locations, not --locations.
(AT_CHECK_CALC_GLR): Use %glr-parser, not %glr_parser.