The indicator is based on XCB-XKB and `libxkbcommon`. It can be tested
using the following configuration:
```
bar-list = ["bar"];
bar: {
position: "top";
block-list: ["ya_xkb"];
ya_xkb: {
exec: "YABAR_KEYBOARD_LAYOUT";
interval: 1;
};
}
```
The followinng new dependencies have been introduced:
- libxkbcommon-dev
- libxkbcommon-x11-dev
- libxcb-xkb-dev
Both work with libxcb and allow the usage of XKB through an XCB session.
In this case the session `ya.c` created by `src/ya_exec.c` can be used
for this indicator, so no extra X11 logic is needed.
