Re: [PATCH] Revert 'Fix logic error in _AC_PROG_LEX_YYTEXT_DECL (#109320)'

[Paul Eggert]

On 7/16/20 7:10 AM, Zack Weinberg wrote:

> I propose to make the following additional changes, instead of reverting
> the patch:
>
>   - Change the conftest.l used by _AC_PROG_LEX_YYTEXT_DECL so that it
> defines yywrap itself (it already defines main).  Thus, LEXLIB will
> only be set to -ll or -lfl if there's something in there *besides*
> yywrap and main that the generated scanner needs.  Document this.
>
>   - Add a new macro, tentatively AC_FUNC_YYWRAP([action-if-not-found]),
> that tries to find a definition of yywrap in libl and libfl, sets
> LEXLIB accordingly, and failing that executes action-if-not-found,
> which defaults to AC_LIBOBJ([yywrap]).
>
> What do you think?

Unfortunately I read this email *after* looking at the bug reports on Savannah. 
(I *hate* having multiple streams of bug reports! Can't we standardize on just 
one? If it were up to me I'd stop using Savannah and stick with just 
bug-autoconf like the Autoconf manual says - but I digress.)

The patch I installed was simpler and more conservative than what you proposed. 
It gives up on 'flex' and sets LEX back to ":" if any of the 
_AC_PROG_LEX_YYTEXT_DECL tests fail.

I had not considered the fact that -lfl is basically useless. I like your first 
suggestion, as I expect it'll make AC_PROG_LEX more useful and will encourage 
people to stop linking with -lfl which is a good thing. I'm not sure that the 
AC_FUNC_YYWRAP macro would be worth the trouble.