Re: [PATCH 1/3] configure: Enforce gnu99 C language standard

[Leif Lindholm <leif@nuviainc.com>]

On Thu, Apr 02, 2020 at 17:07:48 +0200, Daniel Kiper wrote:
> Commit d5a32255d (misc: Make grub_strtol() "end" pointers have safer
> const qualifiers) introduced "restrict" keyword into some functions
> definitions. This keyword was introduced in C99 standard. However, some
> compilers by default may use C89 or something different. This behavior
> leads to the breakage during builds when c89 or gnu89 is in force. So,
> let's enforce gnu99 C language standard for all compilers. This way
> a bit random build issue will be fixed and the GRUB source will be
> build consistently regardless of type and version of the compiler.
> 
> It was decided to use gnu99 C language standard because it fixes the
> issue mentioned above and also provides some useful extensions which are
> used here and there in the GRUB source. Potentially we can use gnu11 too.
> However, this may reduce pool of older compilers which can be used to
> build the GRUB. So, let's live with gnu99 until we do not discover that
> we strongly require a feature from newer C standard.
> 
> Signed-off-by: Daniel Kiper <daniel.kiper@oracle.com>
> ---
>  configure.ac | 11 +++++++++--
>  1 file changed, 9 insertions(+), 2 deletions(-)
> 
> diff --git a/configure.ac b/configure.ac
> index 88c0adbae..b7f40a1c3 100644
> --- a/configure.ac
> +++ b/configure.ac
> @@ -75,9 +75,16 @@ grub_TRANSFORM([grub-sparc64-setup])
>  grub_TRANSFORM([grub-render-label])
>  grub_TRANSFORM([grub-file])
>  
> -# Optimization flag.  Allow user to override.
> +if test "x$BUILD_CFLAGS" = x; then
> +  BUILD_CFLAGS='-std=gnu99'
> +fi
> +
> +if test "x$HOST_CFLAGS" = x; then
> +  HOST_CFLAGS='-std=gnu99'
> +fi
> +
>  if test "x$TARGET_CFLAGS" = x; then
> -  TARGET_CFLAGS="$TARGET_CFLAGS -Os"
> +  TARGET_CFLAGS='-Os -std=gnu99'
>  fi

Do these not add -std=gnu99 only if *_CFLAGS are not specified?
Would we not want to override these always?

For example, Debian/Ubuntu override HOST_CFLAGS when building grub.

/
    Leif

>  
>  # Default HOST_CPPFLAGS
> -- 
> 2.11.0
>