[gentoo-dev] [PATCH v2] profiles/base: add cache vars for -Wimplicit-function-declaration silencing

[gentoo-dev] [PATCH v2] profiles/base: add cache vars for -Wimplicit-function-declaration silencing

[Sam James]

Autoconf has a builtin check to try figure out how to make the compiler
error out on implicit function declarations. This check necessarily emits
such a warning/error. We know that -Werror=implicit-function-declaration
will work on any compiler we care about, so just force that to avoid noise.

This means we don't have to try whitelist 'strchr'.

v2: drop 'export' as PMS doesn't allow it in make.defaults.

Signed-off-by: Sam James <sam@gentoo.org>
---
 profiles/base/make.defaults | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/profiles/base/make.defaults b/profiles/base/make.defaults
index ab69dbfae58ee..68ff36a90cc8d 100644
--- a/profiles/base/make.defaults
+++ b/profiles/base/make.defaults
@@ -181,3 +181,9 @@ ADA_TARGET="gnat_2021"
 # Default targets for lua{,-single}.eclass
 LUA_SINGLE_TARGET="lua5-1"
 LUA_TARGETS="lua5-1"
+
+# Sam James <sam@gentoo.org> (2023-02-28)
+# Reduce -Wimplicit-function-declaration noise from autoconf. Any compilers
+# we care about should match these anyway. See https://wiki.gentoo.org/wiki/Modern_C_porting.
+ac_cv_c_undeclared_builtin_options="none needed"
+gl_cv_compiler_check_decl_option="-Werror=implicit-function-declaration"
-- 
2.39.2

Re: [gentoo-dev] [PATCH v2] profiles/base: add cache vars for -Wimplicit-function-declaration silencing

[Michał Górny]

On Tue, 2023-02-28 at 19:03 +0000, Sam James wrote:
> Autoconf has a builtin check to try figure out how to make the compiler
> error out on implicit function declarations. This check necessarily emits
> such a warning/error. We know that -Werror=implicit-function-declaration
> will work on any compiler we care about, so just force that to avoid noise.
> 
> This means we don't have to try whitelist 'strchr'.
> 
> v2: drop 'export' as PMS doesn't allow it in make.defaults.
> 
> Signed-off-by: Sam James <sam@gentoo.org>
> ---
>  profiles/base/make.defaults | 6 ++++++
>  1 file changed, 6 insertions(+)
> 
> diff --git a/profiles/base/make.defaults b/profiles/base/make.defaults
> index ab69dbfae58ee..68ff36a90cc8d 100644
> --- a/profiles/base/make.defaults
> +++ b/profiles/base/make.defaults
> @@ -181,3 +181,9 @@ ADA_TARGET="gnat_2021"
>  # Default targets for lua{,-single}.eclass
>  LUA_SINGLE_TARGET="lua5-1"
>  LUA_TARGETS="lua5-1"
> +
> +# Sam James <sam@gentoo.org> (2023-02-28)
> +# Reduce -Wimplicit-function-declaration noise from autoconf. Any compilers
> +# we care about should match these anyway. See https://wiki.gentoo.org/wiki/Modern_C_porting.
> +ac_cv_c_undeclared_builtin_options="none needed"
> +gl_cv_compiler_check_decl_option="-Werror=implicit-function-declaration"

LGTM.  Thanks!

-- 
Best regards,
Michał Górny