meson does (did) not accept gnu89 as an option when building objective C

[snarkhunter (Steve Langer)]

On Big Sur 11.5.2, glib2 doesn't get past the configuration step when default variants include +quartz:

meson.build:655:2: ERROR: Value "gnu89" (of type "string") for combo option "C language standard to use" is not one of the choices. Possible choices are (as string): "none", "c89", "c99", "c11", "c17", "gnu99", "gnu11".

[snarkhunter (Steve Langer)]

log file

[ryandesign (Ryan Carsten Schmidt)]

This appears to have been caused by updating meson to 0.59.1. This problem didn't occur when using meson 0.58.1.

glib2 is outdated. Possibly updating glib2 will solve this. However, it seems like a meson bug to me. Why wouldn't gnu89 be valid?

[larryv (Lawrence Velázquez)]

Replying to snarkhunter:

On Big Sur 11.5.2, glib2 doesn't get past the configuration step when default variants include +quartz:

It occurs with +x11 as well, and I'm on 10.14.6.

[kencu (Ken)]

it seems to be failing on the objectivec sanity test... the c tests all passed.

the meson 59 release notes indicate the objectivec flag handling changed.

that's as far as I got tonight.

[danchr (Dan Villiom Podlaski Christiansen)]

I've posted a PR that should fix this:

​https://github.com/macports/macports-ports/pull/12154

Essentially, I just search their Gitlab repository for similar issues, and found one. It's a couple of years old, but simply changes gnu89 to gnu99.

[kencu (Ken)]

Yeah - it would still be nice to understand why this is happening, but if just changing it to gnu99 and forgetting about the why gets us moving on, that is good enough for me.

we may see this again in other ports perhaps (doubt it -- who else would be forcing gnu89?). But if so, we can do the same thing.

If there are other issues with the objective-c flags that show up, we'll find them soon enough and then have to understand it.

[kencu (Ken)]

OK, it looks like the issue is here in

mesonbuild/compilers/objc.py

they have (incorrectly I believe) excluded gnu89 from the available options for the C std.

If we can verify somehow to them that gnu89 should be an accepted option for ObjC, then perhaps they can add it.

Or we can patch it in as an accepted option ourselves, as it was (apparently) previously accepted.

    def get_options(self) -> 'coredata.KeyedOptionDictType':
        opts = super().get_options()
        opts.update({
            OptionKey('std', machine=self.for_machine, lang='c'): coredata.UserComboOption(
                'C language standard to use',
                ['none', 'c89', 'c99', 'c11', 'c17', 'gnu99', 'gnu11'],
                'none',
            )
        })
        return opts

[kencu (Ken)]

changing that line to

['none', 'c89', 'c99', 'c11', 'c17', 'gnu89', 'gnu99', 'gnu11'],

and all is fine again, glib2 builds through

[larryv (Lawrence Velázquez)]

Replying to kencu:

Or we can patch it in as an accepted option ourselves, as it was (apparently) previously accepted.

It was never accepted; they just ​did not check before. Probably an oversight, as gnu89 clearly works.

[kencu (Ken)]

In 6f1a759b132b0e9ce4690b7bffa9e09163a167a7/macports-ports (master):

meson: accept gnu89 for ObjC

see: #63462

[ryandesign (Ryan Carsten Schmidt)]

I filed an upstream bug report: ​https://github.com/mesonbuild/meson/issues/9237

[danchr (Dan Villiom Podlaski Christiansen)]

In 8dd0f5d9f8992743dbe65cf69047ca0def657440/macports-ports (master):

glib2: use C99 mode

Using C89 with GNU extensions used to break the build, but it's
generally invalid, so we might as well fix it. Upstream has a fairly
old bug[1] reporting this, so I just applied the fix directly.[2]

[1] ​https://gitlab.gnome.org/GNOME/glib/-/issues/1662
[2] ​https://gitlab.gnome.org/GNOME/glib/-/merge_requests/606

See: #63462

[ryandesign (Ryan Carsten Schmidt)]

Please see the comment at the top of the glib2 portfile:

# Please keep the glib2 and glib2-devel ports as similar as possible.

[rubendibattista (Ruben Di Battista)]

Updating the glib2 version makes it work for me: ​https://github.com/macports/macports-ports/pull/12203

[kencu (Ken)]

[6f1a759b132b0e9ce4690b7bffa9e09163a167a7/macports-ports]

[kencu (Ken)]

the next version of meson fixes this and adds a few more missing standards we would have eventually tripped over.