Re: Still a few flaws in configure's default CFLAGS selection

Tom Lane wrote:
> While fooling with adding -fno-strict-aliasing to configure, I realized
> that there are still some oddities about its selection of CFLAGS. The
> problems stem from the fact that autoconf will always select a default
> value of CFLAGS that includes "-g", if the compiler accepts "-g" at all.
> This has a couple of consequences:
>
> 1. --enable-debug is nearly useless, since unless you've manually
> specified CFLAGS, what you're going to get will include -g anyway.
>
> 2. The code Bruce put in to default to "-O" on non-gcc compilers
> will never actually fire.

I see that now. I saw in configure:

if test "$ac_test_CFLAGS" = set; then
CFLAGS=$ac_save_CFLAGS
elif test $ac_cv_prog_cc_g = yes; then
if test "$GCC" = yes; then
CFLAGS="-g -O2"
else
CFLAGS="-g"
fi
else
if test "$GCC" = yes; then
CFLAGS="-O2"
else
CFLAGS=
fi
fi

and assumed the CFLAGS= line was the default, and thought the
$ac_cv_prog_cc_g = yes test was for debug enabled. Now I see it just
checks if -g works and uses it unconditionally. That is bizarre. I
was never even fond of configure defaulting to -O2. It is a fine
default, but the CFLAGS default should be our decision, not configure.

> It would be fairly easy to override autoconf's behavior, but I wonder
> whether that will surprise people who are used to the "standard"
> behavior of autoconf scripts. Personally I've always felt that
> defaulting to -g was a bizarre and unwise choice on the part of the
> autoconf developers, but maybe someone out there wants to defend it?

Agreed. What does autoconf know about our project? Nothing. We should
not default to their compile flages.

--
Bruce Momjian | http://candle.pha.pa.us
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