[Buildroot] host-m4 build on Fedora 42 fails

[Buildroot] host-m4 build on Fedora 42 fails

[Joseph Zikusooka]

Recently upgraded to Fedora 42 and since then I am unable to compile
buildroot.  Make fails at the host-m4 package.
I looked up several sources and found this:
https://lists.gnu.org/archive/html/m4-discuss/2025-02/msg00000.html

The work around on Fedora 42 was to build m4 with the environment
flags as follows:
CFLAGS='-std=gnu17' ./configure && make

I tried to patch m4.mk as follows, but the build is still failing.  Any ideas?

--- a/m4.mk     2025-04-18 17:02:01.174923317 +0300
+++ b/m4.mk     2025-04-18 17:03:29.285694673 +0300
@@ -10,4 +10,7 @@
 M4_LICENSE = GPL-3.0+
 M4_LICENSE_FILES = COPYING

+M4_CONF_ENV = CFLAGS="-std=gnu17"
+M4_MAKE_ENV = CFLAGS="-std=gnu17"
+
 $(eval $(host-autotools-package))

-- 
Joseph Zikusooka (ZIK)
_______________________________________________
buildroot mailing list
buildroot@buildroot.org
https://lists.buildroot.org/mailman/listinfo/buildroot

Re: [Buildroot] host-m4 build on Fedora 42 fails

[Julien Olivain]

Hi Joseph,

Thanks for reporting the issue.

On 18/04/2025 16:14, Joseph Zikusooka wrote:
> Recently upgraded to Fedora 42 and since then I am unable to compile
> buildroot.  Make fails at the host-m4 package.
> I looked up several sources and found this:
> https://lists.gnu.org/archive/html/m4-discuss/2025-02/msg00000.html
> 
> The work around on Fedora 42 was to build m4 with the environment
> flags as follows:
> CFLAGS='-std=gnu17' ./configure && make
> 
> I tried to patch m4.mk as follows, but the build is still failing.  Any 
> ideas?
> 
> --- a/m4.mk     2025-04-18 17:02:01.174923317 +0300
> +++ b/m4.mk     2025-04-18 17:03:29.285694673 +0300
> @@ -10,4 +10,7 @@
>  M4_LICENSE = GPL-3.0+
>  M4_LICENSE_FILES = COPYING
> 
> +M4_CONF_ENV = CFLAGS="-std=gnu17"
> +M4_MAKE_ENV = CFLAGS="-std=gnu17"
> +

To workaround this gcc15 issue with the current m4
version 1.4.19, you should probably pass the CFLAGS as:

HOST_M4_CONF_ENV = CFLAGS="$(HOST_CFLAGS) -std=gnu17"

Also, there is an upcoming m4 release which will fix
this gcc 15 issue. See:
https://git.savannah.gnu.org/cgit/m4.git/commit/?h=branch-1.4&id=a22c9802dd7e724eaefb21dc21d84ac2d3a49c89

More specifically:
"
** Update to comply with newer C standards, and inherit portability
    improvements from gnulib.
"

If this new m4 release is not published in the coming days/weeks
please submit an updated version of this patch to fix this issue.
Please also add a comment that this CFLAGS modification is needed
for m4-1.4.19 and host-gcc15 and should be removed in the next
bump to 1.4.20.

Best regards,

Julien.
_______________________________________________
buildroot mailing list
buildroot@buildroot.org
https://lists.buildroot.org/mailman/listinfo/buildroot

Re: [Buildroot] host-m4 build on Fedora 42 fails

[Joseph Zikusooka]

[-- Attachment #1.1: Type: text/plain, Size: 2244 bytes --]

Hi Julien,

Thanks for the info and the workaround tip!

I updated my patch to use CFLAGS="$(HOST_CFLAGS) -std=gnu17" like you
suggested, but the build still fails with GCC 15 and m4 1.4.19 - same
errors as before. Strangely, if I build m4 outside the buildroot
environment with those flags, it works fine.

Any idea what else could be causing the workaround to fail in buildroot?
Are there other flags or tweaks I could try in m4.mk until the new m4
release is out?

Regards,
Joseph Zikusooka (ZIK)

On Sat, Apr 19, 2025, 3:29 PM Julien Olivain <ju.o@free.fr> wrote:

> Hi Joseph,
>
> Thanks for reporting the issue.
>
> On 18/04/2025 16:14, Joseph Zikusooka wrote:
> > Recently upgraded to Fedora 42 and since then I am unable to compile
> > buildroot.  Make fails at the host-m4 package.
> > I looked up several sources and found this:
> > https://lists.gnu.org/archive/html/m4-discuss/2025-02/msg00000.html
> >
> > The work around on Fedora 42 was to build m4 with the environment
> > flags as follows:
> > CFLAGS='-std=gnu17' ./configure && make
> >
> > I tried to patch m4.mk as follows, but the build is still failing.  Any
> > ideas?
> >
> > --- a/m4.mk     2025-04-18 17:02:01.174923317 +0300
> > +++ b/m4.mk     2025-04-18 17:03:29.285694673 +0300
> > @@ -10,4 +10,7 @@
> >  M4_LICENSE = GPL-3.0+
> >  M4_LICENSE_FILES = COPYING
> >
> > +M4_CONF_ENV = CFLAGS="-std=gnu17"
> > +M4_MAKE_ENV = CFLAGS="-std=gnu17"
> > +
>
> To workaround this gcc15 issue with the current m4
> version 1.4.19, you should probably pass the CFLAGS as:
>
> HOST_M4_CONF_ENV = CFLAGS="$(HOST_CFLAGS) -std=gnu17"
>
> Also, there is an upcoming m4 release which will fix
> this gcc 15 issue. See:
>
> https://git.savannah.gnu.org/cgit/m4.git/commit/?h=branch-1.4&id=a22c9802dd7e724eaefb21dc21d84ac2d3a49c89
>
> More specifically:
> "
> ** Update to comply with newer C standards, and inherit portability
>     improvements from gnulib.
> "
>
> If this new m4 release is not published in the coming days/weeks
> please submit an updated version of this patch to fix this issue.
> Please also add a comment that this CFLAGS modification is needed
> for m4-1.4.19 and host-gcc15 and should be removed in the next
> bump to 1.4.20.
>
> Best regards,
>
> Julien.
>

[-- Attachment #1.2: Type: text/html, Size: 3611 bytes --]

[-- Attachment #2: Type: text/plain, Size: 150 bytes --]

_______________________________________________
buildroot mailing list
buildroot@buildroot.org
https://lists.buildroot.org/mailman/listinfo/buildroot

Re: [Buildroot] host-m4 build on Fedora 42 fails

[Julien Olivain]

Hi Joseph,

On 19/04/2025 18:56, Joseph Zikusooka wrote:
> Hi Julien,
> 
> Thanks for the info and the workaround tip!
> 
> I updated my patch to use CFLAGS="$(HOST_CFLAGS) -std=gnu17" like you
> suggested, but the build still fails with GCC 15 and m4 1.4.19 - same
> errors as before. Strangely, if I build m4 outside the buildroot
> environment with those flags, it works fine.
> 
> Any idea what else could be causing the workaround to fail in
> buildroot? Are there other flags or tweaks I could try in m4.mk [1]
> until the new m4 release is out?

I just tried adding the line I suggested in package/m4/m4.mk:
HOST_M4_CONF_ENV = CFLAGS="$(HOST_CFLAGS) -std=gnu17"

On a Fedora 42 host system (updated as of now), it solves the
host-m4 build issue. You need to restart from a clean build,
though.

I tested with the commands:

     make qemu_aarch64_virt_defconfig
     make clean
     make

Could you check on your side, please?

Best regards,

Julien.
_______________________________________________
buildroot mailing list
buildroot@buildroot.org
https://lists.buildroot.org/mailman/listinfo/buildroot

Re: [Buildroot] host-m4 build on Fedora 42 fails

[Joseph Zikusooka]

Hi Julien,

Thanks, that solved the problem! I needed to run "make distclean"
before building with the updated m4.mk file. While we wait for a new
m4 release from upstream, I’m sharing the patch that worked for me in
case anyone else encounters this issue.

--- a/package/m4/m4.mk    2025-04-03 13:59:27.224254338 +0300
+++ b/package/m4/m4.mk    2025-04-21 21:04:22.107546262 +0300
@@ -10,4 +10,8 @@
 M4_LICENSE = GPL-3.0+
 M4_LICENSE_FILES = COPYING

+HOST_M4_CONF_ENV = CFLAGS="$(HOST_CFLAGS) -std=gnu17"
+
+HOST_M4_CONF_ENV = CFLAGS="$(HOST_CFLAGS) -std=gnu17"
+
 $(eval $(host-autotools-package))

On Mon, Apr 21, 2025 at 5:00 PM Julien Olivain <ju.o@free.fr> wrote:
>
> Hi Joseph,
>
> On 19/04/2025 18:56, Joseph Zikusooka wrote:
> > Hi Julien,
> >
> > Thanks for the info and the workaround tip!
> >
> > I updated my patch to use CFLAGS="$(HOST_CFLAGS) -std=gnu17" like you
> > suggested, but the build still fails with GCC 15 and m4 1.4.19 - same
> > errors as before. Strangely, if I build m4 outside the buildroot
> > environment with those flags, it works fine.
> >
> > Any idea what else could be causing the workaround to fail in
> > buildroot? Are there other flags or tweaks I could try in m4.mk [1]
> > until the new m4 release is out?
>
> I just tried adding the line I suggested in package/m4/m4.mk:
> HOST_M4_CONF_ENV = CFLAGS="$(HOST_CFLAGS) -std=gnu17"
>
> On a Fedora 42 host system (updated as of now), it solves the
> host-m4 build issue. You need to restart from a clean build,
> though.
>
> I tested with the commands:
>
>      make qemu_aarch64_virt_defconfig
>      make clean
>      make
>
> Could you check on your side, please?
>
> Best regards,
>
> Julien.



-- 
Joseph Zikusooka
_______________________________________________
buildroot mailing list
buildroot@buildroot.org
https://lists.buildroot.org/mailman/listinfo/buildroot

Re: [Buildroot] host-m4 build on Fedora 42 fails

[Joseph Zikusooka]

I think I rushed the previous patch - here’s the corrected version.


--- a/package/m4/m4.mk    2025-04-03 13:59:27.224254338 +0300
+++ b/package/m4/m4.mk     2025-04-21 21:41:45.589717302 +0300
@@ -10,4 +10,6 @@
 M4_LICENSE = GPL-3.0+
 M4_LICENSE_FILES = COPYING

+HOST_M4_CONF_ENV = CFLAGS="$(HOST_CFLAGS) -std=gnu17"
+
 $(eval $(host-autotools-package))

On Mon, Apr 21, 2025 at 9:21 PM Joseph Zikusooka <josephzik@gmail.com> wrote:
>
> Hi Julien,
>
> Thanks, that solved the problem! I needed to run "make distclean"
> before building with the updated m4.mk file. While we wait for a new
> m4 release from upstream, I’m sharing the patch that worked for me in
> case anyone else encounters this issue.
>
> --- a/package/m4/m4.mk    2025-04-03 13:59:27.224254338 +0300
> +++ b/package/m4/m4.mk    2025-04-21 21:04:22.107546262 +0300
> @@ -10,4 +10,8 @@
>  M4_LICENSE = GPL-3.0+
>  M4_LICENSE_FILES = COPYING
>
> +HOST_M4_CONF_ENV = CFLAGS="$(HOST_CFLAGS) -std=gnu17"
> +
> +HOST_M4_CONF_ENV = CFLAGS="$(HOST_CFLAGS) -std=gnu17"
> +
>  $(eval $(host-autotools-package))
>
> On Mon, Apr 21, 2025 at 5:00 PM Julien Olivain <ju.o@free.fr> wrote:
> >
> > Hi Joseph,
> >
> > On 19/04/2025 18:56, Joseph Zikusooka wrote:
> > > Hi Julien,
> > >
> > > Thanks for the info and the workaround tip!
> > >
> > > I updated my patch to use CFLAGS="$(HOST_CFLAGS) -std=gnu17" like you
> > > suggested, but the build still fails with GCC 15 and m4 1.4.19 - same
> > > errors as before. Strangely, if I build m4 outside the buildroot
> > > environment with those flags, it works fine.
> > >
> > > Any idea what else could be causing the workaround to fail in
> > > buildroot? Are there other flags or tweaks I could try in m4.mk [1]
> > > until the new m4 release is out?
> >
> > I just tried adding the line I suggested in package/m4/m4.mk:
> > HOST_M4_CONF_ENV = CFLAGS="$(HOST_CFLAGS) -std=gnu17"
> >
> > On a Fedora 42 host system (updated as of now), it solves the
> > host-m4 build issue. You need to restart from a clean build,
> > though.
> >
> > I tested with the commands:
> >
> >      make qemu_aarch64_virt_defconfig
> >      make clean
> >      make
> >
> > Could you check on your side, please?
> >
> > Best regards,
> >
> > Julien.
>
>
>
> --
> Joseph Zikusooka



-- 
Joseph Zikusooka
_______________________________________________
buildroot mailing list
buildroot@buildroot.org
https://lists.buildroot.org/mailman/listinfo/buildroot

Re: [Buildroot] host-m4 build on Fedora 42 fails

[Julien Olivain]

Hi Joseph,

On 21/04/2025 21:02, Joseph Zikusooka wrote:
> I think I rushed the previous patch - here’s the corrected version.
> 
> 
> --- a/package/m4/m4.mk    2025-04-03 13:59:27.224254338 +0300
> +++ b/package/m4/m4.mk     2025-04-21 21:41:45.589717302 +0300
> @@ -10,4 +10,6 @@
>  M4_LICENSE = GPL-3.0+
>  M4_LICENSE_FILES = COPYING
> 
> +HOST_M4_CONF_ENV = CFLAGS="$(HOST_CFLAGS) -std=gnu17"
> +
>  $(eval $(host-autotools-package))
> 
> On Mon, Apr 21, 2025 at 9:21 PM Joseph Zikusooka <josephzik@gmail.com> 
> wrote:
>> 
>> Hi Julien,
>> 
>> Thanks, that solved the problem! I needed to run "make distclean"
>> before building with the updated m4.mk file. While we wait for a new
>> m4 release from upstream, I’m sharing the patch that worked for me in
>> case anyone else encounters this issue.

Thank you for the confirmation. Could you send a new updated patch
with this fix, please?

Best regards,

Julien.
_______________________________________________
buildroot mailing list
buildroot@buildroot.org
https://lists.buildroot.org/mailman/listinfo/buildroot