* src/output.c (prepare): Delete insertion of previous muscles,

* src/output.c (prepare): Delete insertion of previous muscles,
and insert the `prefix' muscles.
* src/macrotab.c (macro_init): Likewise.
(macro_init): Initialization prefix directive by `yy'.
* src/bison.simple: Substitute all %%yylex, %%yychar, %%yylval,
%%yydebug, %%yyerror, %%yynerrs and %%yyparse by yylex, yychar,
yylval, yydebug, yyerror, yynerrs and yyparse.
New directive `#define' to substitute yydebug, ... with option
name_prefix.