2.4.0 fails to build with Clang < 18 and GCC < 14

[jbeich]

cagebreak still builds fine with -std=c11 and (unlike wlroots where -std=c23 is autodetected) doesn't use __VA_OPT__. Why intentionally break then?

$ cc --version
FreeBSD clang version 17.0.6 (https://github.com/llvm/llvm-project.git llvmorg-17.0.6-0-g6009708b4367)
Target: x86_64-unknown-freebsd13.3
Thread model: posix
InstalledDir: /usr/bin

$ meson setup _build
The Meson build system
Version: 1.6.0.rc1
Source dir: .../cagebreak-2.4.0
Build dir: .../cagebreak-2.4.0/_build
Build type: native build
meson_options.txt:3: WARNING: Project does not target a minimum version but uses feature deprecated since '1.1.0': "boolean option" keyword argument "value" of type str. use a boolean, not a string
meson_options.txt:4: WARNING: Project does not target a minimum version but uses feature deprecated since '1.1.0': "boolean option" keyword argument "value" of type str. use a boolean, not a string
meson_options.txt:5: WARNING: Project does not target a minimum version but uses feature deprecated since '1.1.0': "boolean option" keyword argument "value" of type str. use a boolean, not a string
Project name: cagebreak
Project version: 2.4.0

meson.build:3:0: ERROR: None of values ['c23'] are supported by the C compiler. Possible values for option "C_std" are ['none', 'c89', 'c99', 'c11', 'c17', 'c18', 'c2x', 'gnu89', 'gnu99', 'gnu11', 'gnu17', 'gnu18', 'gnu2x']

A full log can be found at .../cagebreak-2.4.0/_build/meson-logs/meson-log.txt

[project-repo]

Hi jbeich,
Sorry for this. The issue is that the code is strictly speaking not
std<23 compatible. (ISO C99 requires at least one argument for the "..."
in a variadic macro). The only possibility we saw for fixing this was to
require at least std=3Dc23. So we had the tension between having a
release build with no warnings basically for free vs a big cost of
conforming to new warnings for an older version of C - though it did
break stuff, even for us (fuzzing) it seemed like the best option.

We are very open to ideas that address the issue.

Cheers
project-repo

[jbeich]

ISO C99 requires at least one argument for the "..." in a variadic macro

Clang doesn't print this warning in -std=c11 mode. See downstream build log after applying workaround.

[project-repo]

Thank you very much for your swift reply, we will include the patch for meson.build in our next release, which will hopefully occur sooner than last time.

cheers
project-repo