Re: [PATCH] RFC: build-sys: drop dtc submodule

[Daniel P . Berrangé]

On Wed, Aug 25, 2021 at 07:12:10PM +0100, Peter Maydell wrote:
> On Wed, 25 Aug 2021 at 14:28, Philippe Mathieu-Daudé <f4bug@amsat.org> wrote:
> >
> > On 8/25/21 2:43 PM, marcandre.lureau@redhat.com wrote:
> > > From: Marc-André Lureau <marcandre.lureau@redhat.com>
> > >
> > > DTC is widely available, we could consider to stop bundling it.
> > >
> > > curl -s 'https://repology.org/api/v1/project/dtc' |  \
> > >    jq -r 'group_by(.repo) | .[] | "\(.[0].repo): \(map(.version))"' | \
> > >    egrep -i 
> > > 'ubuntu_18|debian_old|rhel|centos|bsd|suse_leap_15_2|sles|homebrew|pkgsrc'
> > >
> > > centos_8: ["1.6.0","1.6.0"]
> > > debian_oldstable: ["1.4.7"]
> > > freebsd: ["1.6.0"]
> > > homebrew: ["1.6.1"]
> > > openbsd: ["1.6.0"]
> > > opensuse_leap_15_2: ["1.5.1","1.5.1"]
> > > pkgsrc_current: ["1.4.7"]
> > > ubuntu_18_04: ["1.4.5"]
> > >
> > > MinGW package on Fedora pending review.
> > > (https://bugzilla.redhat.com/show_bug.cgi?id=1997511)
> > >
> > > Debian is lacking the MinGW package.
> > >
> > > Signed-off-by: Marc-André Lureau <marcandre.lureau@redhat.com>
> > > ---
> > >  configure         | 22 +-------------------
> > >  meson.build       | 53 ++++++++---------------------------------------
> > >  .gitmodules       |  3 ---
> > >  dtc               |  1 -
> > >  meson_options.txt |  3 ---
> > >  5 files changed, 10 insertions(+), 72 deletions(-)
> > >  delete mode 160000 dtc
> >
> > Does this fix https://gitlab.com/qemu-project/qemu/-/issues/255 ?
> > "Build on sparc64 fails with "undefined reference to `fdt_check_full'"
> 
> That bug sounds like it indicates that we can't use this patch:
> a comment in the bug says that fdt_check_full() (which we use)
> was only added in libfdt 1.5.1. So the libfdt version we need
> is still not available in several of the distros we care about.
> 
> I suspect the bug you link to may have been fixed -- certainly
> meson.build appears to be specifically looking for fdt_check_full()
> so we should never try to compile with a libfdt that doesn't have it.

It is slightly more complicated - the fdt_check_full function exists
in all the distros we target AFAICT, but libfdt's ELF symbols file 
never recorded its existance. So if you static link to libfdt you 
get fdt_check_full but if you dynamic link it is inaccessible :-(

Regards,
Daniel
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