Re: Wrong order of preprocessor and compiler flags

[Evgeny Grin]

Hello Karl,


On 28.03.2022 0:22, Karl Berry wrote:
> It seems the basic inconsistency is whether CPPFLAGS is considered a
> "user variable" or not. In earlier eras, it wasn't, but from your msg,
> I gather it is now.
>
> The GNU standards node about it, that you mentioned,
>    https://www.gnu.org/prep/standards/standards.html#Command-Variables
> does not clearly state it one way or another. But its example shows
> CFLAGS after CPPFLAGS.

The same example puts "-I." into ALL_CFLAGS, which makes even harder to 
guess the right idea how to use CPPFLAGS.

> Thus I think a prior step is to write bug-standards@gnu.org and suggest
> clarifying the status of CPPFLAGS, its relationship to CFLAGS, etc.

Definitely makes sense.
I'll write to the standards list.

> We could consider changing automake to follow autoconf even if the GCS
> is not changed, but it would be better if the GCS were clear.
>
>      2. Use AM_CFLAGS CFLAGS AM_CPPFLAGS CPPFLAGS. This is more aligned with
>      current flags grouping, but CFLAGS will not override definitions in
>      AM_CPPFLAGS (less aligned with GNU Standards).
>
> It seems wrong (and disastrously backwards-incompatible) to me for
> CFLAGS not to override AM_everything. Your option 1:
>
>      1. Use AM_CFLAGS AM_CPPFLAGS CFLAGS CPPFLAGS. I think this is the best
>      option. As required by GNU Standards, CFLAGS still override all
>      upstream-defined flags.
>
> seems like the best option to me too. --thanks, karl.

--
Evgeny