Use werror for gnome.generate_gir(fatal_warnings:)

[tristan957]

In addition to the kwarg, Meson will now read werror to determine whether to turn on this warning.

[tristan957]

cc @ebassi. Saw your introspection talk, so thought I would help you out. Does the boolean logic match what you expect to happen with backward compatibility in mind?

[ebassi]

Yes, this is what I had in mind. There's still the question as to whether we want fatal_warnings to override werror, i.e. the case where you pass --werror but fatal_warnings: false should take precedence. I don't have a strong opinion on that regard.

[tristan957]

Cool. Thanks for your feedback.

[eli-schwartz]

I agree, that fatal_warnings should be updated to track either boolean values from meson.build or default=None as a sentinel for "no value passed in meson.build", so that it can check the global "werror" option only when fatal_warnings is None.

[tristan957]

Eli, would changing the default not be a breaking change?

[eli-schwartz]

The default is werror=false and fatal_warnings: false, so after this PR is implemented, users would still not have fatal warnings unless they somehow opted into it.

Not sure what you mean by that.