yacc.c does not prototype yyparse in the header

[Akim Demaille]

Hi all,

Bruce Korb just pointed out to me that Bison 2.5.1 does
not prototype yyparse in the generated header, with yacc.c.
The other skeletons do.  I don't understand why.  I see
nothing in the documentation of Yacc that prevents this,
and surely this is troublesome for many uses.

I don't think there are problems here.  I guess we only have
to pay attention to handle %prefix via M4, and not via CPP,
to avoid having

#define yyparse fooparse

leak from the header (yet we could also #define it first,
then undefine at the end, in case one would like to use the
name "yyparse" in whatever export %code snippet; but do we
really need to cover this?  The less CPP, the better).

Am I missing something?