Re: CFLAGS default values

[Kevin Ryde]

Bob Friesenhahn <address@hidden> writes:
>
> Agreed.  However, shouldn't Autoconf provide a means for the package
> maintainer to semi-intelligently set a CFLAGS default?

In gmp we establish a CFLAGS before AC_PROG_CC, but with care not to
overwrite a user setting (including an empty setting),

        test_CFLAGS=${CFLAGS+set}
        if test "$test_CFLAGS" != set; then
          # mucho smart options defaulting
          ...
        fi

        AC_PROG_CC

> Unfortunately, the option flags vary across Unix compilers so once you
> go beyond simple '-g' and '-O', it becomes necessary to test if the
> compiler accepts a given option.

Yep, a test run on a sample main, anticipating more or less what
AC_PROG_CC will do.