Re: configure warning suggests an anti-pattern

[Thomas Dickey]

On Sun, Mar 07, 2021 at 07:21:35AM -0500, Thomas Dickey wrote:
> On Sun, Mar 07, 2021 at 11:39:03AM +0100, Bruno Haible wrote:
> > On a Linux/mips machine, I'm compiling 32-bit binaries by setting
> > 
> >   CC="gcc -mabi=32"
> >   CXX="g++ -mabi=32"
> > 
> > This is the recommended way to do, per the Autoconf manual
> > <https://www.gnu.org/savannah-checkouts/gnu/autoconf/manual/autoconf-2.70/html_node/Preset-Output-Variables.html>
> > Quote:
> > 
> >   "If an option selects a 32-bit or 64-bit build on a bi-arch system,
> >    it must be put direcly into CC, e.g., CC='gcc -m64'. This is necessary
> >    for config.guess to work right."

Interestingly enough, according to source history, you are the author of
that comment.  Consider it disregarded.

As of today, there's no correponding advice in the git for config.guess,
which is the proper place to look for relevant information.

It's obviously too late for config.guess to be improved by taking into
account the standard way for specifying compiler options (in $CFLAGS),
since that would immediately break programs which are being configured
by the -Werror clique.

> However, that's a warning message rather than an error.

overbroad, certainly.  But taking this into account:

        https://gcc.gnu.org/onlinedocs/gcc/Preprocessor-Options.html

and this:

        https://gcc.gnu.org/onlinedocs/gcc/Invoking-GCC.html

it's not something that I want to spend a lot of time, tuning
things to work around nonstandard options which have numerous
inconsistencies which preclude a naming convention.  That's only
gcc -- there are other compilers, other design defects.
 
> There's no -Werror in the configure script for users to blindly turn on,
> to aggravate the problem.
> 
> If you're curious to know if the script is doing what it should
> (by moving C preprocessor options _out_ of $CC and $CFLAGS),
> the --verbose option would show the $CC, $CFLAGS and $CPPFLAGS variables.

If you happen to notice a case where the program fails to configure,
that's something that we can discuss on this mailing list.

-- 
Thomas E. Dickey <dickey@invisible-island.net>
https://invisible-island.net
ftp://ftp.invisible-island.net

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