[Buildroot] [PATCH 1/1] package/gcc: undefine NDEBUG directive

[Romain Naour <romain.naour@gmail.com>]

Hello Andreas,

Le 17/06/2021 ? 14:19, Andreas Ziegler a ?crit?:
> GCC performs internal consistency checks that can be controlled with --enable-checking, but not completely removed for all stages of the build. One of these checks uses the assert macro from <assert.h>  Defining NDEBUG removes the assertion code, which is not anticipated in the gcc code. 
> 
> Undefine the NDEBUG flag for package/gcc to preserve assertions. 
> 
> This fixes the following error during build of GCC 10:
> 
> ../../../libgomp/target.c: In function ?gomp_unmap_vars_internal?:
> ../../../libgomp/target.c:1474:9: error: unused variable ?is_tgt_unmapped? [-Werror=unused-variable]
>  1474 |    bool is_tgt_unmapped = gomp_remove_var (devicep, k);
>       |         ^~~~~~~~~~~~~~~
> ../../../libgomp/target.c:1473:28: error: unused variable ?k_tgt? [-Werror=unused-variable]
>  1473 |    struct target_mem_desc *k_tgt = k->tgt;
>       |                            ^~~~~

It seems an error related to Werror being enabled.

Usually we prefer disable Werror while building a package in Buildroot because
any package can trigger new warning with the latest compiler.

Maybe we can use -Wno-error not just when BR2_ENABLE_DEBUG is set:

https://git.buildroot.net/buildroot/commit/?id=dcaf6e75acb4d21c2c31c70b054dac8d18710fcb

Best regards,
Romain

> 
> Signed-off-by: Andreas Ziegler <br015@umbiko.net>
> ---
>  package/gcc/gcc.mk | 3 ++-
>  1 file changed, 2 insertions(+), 1 deletion(-)
> 
> diff --git a/package/gcc/gcc.mk b/package/gcc/gcc.mk
> index ed9b93e50f..4ee32c03a7 100644
> --- a/package/gcc/gcc.mk
> +++ b/package/gcc/gcc.mk
> @@ -90,7 +90,8 @@ HOST_GCC_COMMON_CONF_OPTS = \
>  HOST_GCC_COMMON_CONF_ENV = \
>  	MAKEINFO=missing
>  
> -GCC_COMMON_TARGET_CFLAGS = $(TARGET_CFLAGS)
> +# gcc should not be built with NDEBUG enabled
> +GCC_COMMON_TARGET_CFLAGS = $(TARGET_CFLAGS) -UNDEBUG
>  GCC_COMMON_TARGET_CXXFLAGS = $(TARGET_CXXFLAGS)
>  
>  # used to fix ../../../../libsanitizer/libbacktrace/../../libbacktrace/elf.c:772:21: error: 'st.st_mode' may be used uninitialized in this function [-Werror=maybe-uninitialized]
>