SCons: Use r-strings for wayland-scanner builder command

[akien-mga]

I wonder if there's a static check we could do to spot this without this trial and error?

[Riteo]

Uh I'm not very knowledgeable about python, but this makes sense. How did it work before?

[akien-mga]

It wasn't a problem in the past, but Python 3.12 made this a warning (and I think 3.13 will stop supporting this syntax and error out).

The warnings were these:

/home/akien/Godot/godot/platform/linuxbsd/wayland/SCsub:14: SyntaxWarning: invalid escape sequence '\.'
  "wayland-scanner -c client-header < ${SOURCE} | sed 's:wayland-client-core\.h:../dynwrappers/wayland-client-core-so_wrap\.h:' > ${TARGET}",
/home/akien/Godot/godot/platform/linuxbsd/wayland/SCsub:21: SyntaxWarning: invalid escape sequence '\.'
  "wayland-scanner -c private-code < ${SOURCE} | sed 's:wayland-util\.h:../dynwrappers/wayland-client-core-so_wrap\.h:' > ${TARGET}",

[Riteo]

@akien-mga oh, I see. I think that's actually a great idea from python side, as I missed the r in the first place xD

[Riteo]

Sorry for the double post, but I think that we should do this to the rest of the file at this point, like for example in this part:

    WAYLAND_BUILDERS = {
        "WAYLAND_API_HEADER": Builder(
            action=Action(
                "wayland-scanner -c client-header < ${SOURCE} > ${TARGET}",
                'Generating Wayland client header: "${TARGET}"',
            ),
            single_source=True,
        ),
        "WAYLAND_API_CODE": Builder(
            action=Action(
                "wayland-scanner -c private-code < ${SOURCE} > ${TARGET}",
                'Generating Wayland protocol marshaling code: "${TARGET}"',

[akien-mga]

So far it's only been needed when there's invalid escape codes, like \. here. < and > in these other examples seem fine. But yeah I can apply it to all the wayland-scanner invocations for consistency.