meson: enabling introspection while cross-compiling should be possible
While it needs some prep work (wrapper scripts with qemu-user etc.) it is possible to build gobject introspection files while cross-compiling. So completely disabling it is not nice.
I don't think the default of a boolean option can depend on cross-compiling, can it? Maybe turn 'introspection' into a feature option and default to disabled when cross-compiling?