[1/1] build: allow disabling -Werror

BugLink: https://bugs.launchpad.net/fwts/+bug/2152793

Enforcing "-Werror" in CFLAGS can be helpful from the package
development point of view. It can also become problematic for
distribution maintainers. When updating compilers, those newer
compilers may have different warnings included in "-Wall" or
"-Wextra", or their code analysis just improved.

It is unlikely the fwts developers will update their toolchains
at the same pace as other projects. There is a recent example
with the release of gcc 16 breaking with fwts V26.03.00. Gcc 16
is included in mainstream distributions like Fedora 44 and Arch Linux.

In order to have smoother toolchain transitions, this commit
introduces a new autoconf option "--disable-werror" which will remove
the "-Werror" from the CFLAGS. In that case, the rest of the CFLAGS
are preserved, which means the warning messages will still be reported,
but the build will not fail.

This commit also preserves the original project behavior, to have
"-Werror" enabled by default with a simple "./configure" invocation.

The motivation of this commit is to upstream a package patch that
Buildroot carried over for a decade. See:
https://gitlab.com/buildroot.org/buildroot/-/commit/a9a7a05f39a5cf720822a87c9ac6fa9cf27eaa0e

Signed-off-by: Julien Olivain <ju.o@free.fr>
---
 configure.ac              | 5 +++++
 src/Makefile.am           | 2 +-
 src/lib/src/Makefile.am   | 2 +-
 src/utilities/Makefile.am | 2 +-
 4 files changed, 8 insertions(+), 3 deletions(-)

On 16/05/2026 17.16, Julien Olivain wrote:
> BugLink: https://bugs.launchpad.net/fwts/+bug/2152793
> 
> Enforcing "-Werror" in CFLAGS can be helpful from the package
> development point of view. It can also become problematic for
> distribution maintainers. When updating compilers, those newer
> compilers may have different warnings included in "-Wall" or
> "-Wextra", or their code analysis just improved.
> 
> It is unlikely the fwts developers will update their toolchains
> at the same pace as other projects. There is a recent example
> with the release of gcc 16 breaking with fwts V26.03.00. Gcc 16
> is included in mainstream distributions like Fedora 44 and Arch Linux.
> 
> In order to have smoother toolchain transitions, this commit
> introduces a new autoconf option "--disable-werror" which will remove
> the "-Werror" from the CFLAGS. In that case, the rest of the CFLAGS
> are preserved, which means the warning messages will still be reported,
> but the build will not fail.
> 
> This commit also preserves the original project behavior, to have
> "-Werror" enabled by default with a simple "./configure" invocation.
> 
> The motivation of this commit is to upstream a package patch that
> Buildroot carried over for a decade. See:
> https://gitlab.com/buildroot.org/buildroot/-/commit/a9a7a05f39a5cf720822a87c9ac6fa9cf27eaa0e
> 
> Signed-off-by: Julien Olivain <ju.o@free.fr>
> ---
>   configure.ac              | 5 +++++
>   src/Makefile.am           | 2 +-
>   src/lib/src/Makefile.am   | 2 +-
>   src/utilities/Makefile.am | 2 +-
>   4 files changed, 8 insertions(+), 3 deletions(-)
> 
> diff --git a/configure.ac b/configure.ac
> index fbf487c5..62e43d75 100644
> --- a/configure.ac
> +++ b/configure.ac
> @@ -9,6 +9,11 @@
>   	  LT_INIT
>   	  AC_C_INLINE
>   	  AM_PROG_CC_C_O
> +	  AC_ARG_ENABLE([werror],
> +	  AS_HELP_STRING([--disable-werror], [disable use of -Werror]),
> +		[enable_werror=$enableval], [enable_werror=yes])
> +	  AS_IF([test x$enable_werror = xyes], [WERROR="-Werror"])
> +	  AC_SUBST([WERROR])
>     	  AC_CHECK_FUNCS([localtime_r])
>   	  AC_CHECK_FUNCS([dup2])
>   	  AC_CHECK_FUNCS([getcwd])
> diff --git a/src/Makefile.am b/src/Makefile.am
> index a98a75a1..0e7ba401 100644
> --- a/src/Makefile.am
> +++ b/src/Makefile.am
> @@ -12,7 +12,7 @@ AM_CPPFLAGS = \
>   	-I$(top_srcdir)/src/acpica/source/compiler	\
>   	-I$(top_srcdir)/smccc_test			\
>   	-pthread					\
> -	-Wall -Werror -Wextra				\
> +	-Wall $(WERROR) -Wextra				\
>   	-Wno-address-of-packed-member			\
>   	-Wfloat-equal -Wmissing-declarations		\
>   	-Wno-long-long -Wredundant-decls -Wshadow	\
> diff --git a/src/lib/src/Makefile.am b/src/lib/src/Makefile.am
> index 6534f38f..20b01d1e 100644
> --- a/src/lib/src/Makefile.am
> +++ b/src/lib/src/Makefile.am
> @@ -23,7 +23,7 @@ AM_CPPFLAGS = \
>   	-I$(top_srcdir)/src/acpica/source/compiler	\
>   	-I$(top_srcdir)/smccc_test                      \
>   	-DDATAROOTDIR=\"$(datarootdir)\"		\
> -	-Wall -Werror -Wextra				\
> +	-Wall $(WERROR) -Wextra				\
>   	-Wno-address-of-packed-member
>   
>   pkglib_LTLIBRARIES = libfwts.la
> diff --git a/src/utilities/Makefile.am b/src/utilities/Makefile.am
> index 92c135d1..76a5cdcc 100644
> --- a/src/utilities/Makefile.am
> +++ b/src/utilities/Makefile.am
> @@ -16,7 +16,7 @@
>   # Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
>   #
>   
> -AM_CPPFLAGS = -Wall -Werror -Wextra -DDATAROOTDIR=\"$(datarootdir)\" 	\
> +AM_CPPFLAGS = -Wall $(WERROR) -Wextra -DDATAROOTDIR=\"$(datarootdir)\"	\
>   	-I$(srcdir)/../lib/include
>   
>   bin_PROGRAMS = kernelscan

Reviewed-by: Thomas Huth <thuth@redhat.com>
Tested-by: Thomas Huth <thuth@redhat.com>