The Linux build stopped compiling everywhere: d9e31fd1a wrote the
attribute as [[maybe unused]], with a space instead of an underscore.
An attribute-list is comma-separated, so two bare identifiers are a
parse error rather than an ignorable unknown attribute, and
linux/runner/mpv/mpv_plugin.cc reaches every Linux build.
Use [[maybe_unused]], which is what clang 23's -Wunused-but-set-global
actually checks for, so the diagnostic the original change was chasing
stays suppressed.
edde746
72d15b96a2