sndio: Add module.

- can control sndio: change volume, toggle mute
- appearance is somewhat dynamic: takes muted status into account
- uses polling inside sleeper thread to update values
- uses sioctl_* functions, requires sndio>=1.7.0.

man/waybar-sndio.5.scd

@@ -0,0 +1,83 @@
+waybar-sndio(5)
+
+# NAME
+
+waybar - sndio module
+
+# DESCRIPTION
+
+The *sndio* module displays the current volume reported by sndio(7).
+
+Additionally, you can control the volume by scrolling *up* or *down* while the
+cursor is over the module, and clicking on the module toggles mute.
+
+# CONFIGURATION
+
+*format*: ++
+	typeof: string  ++
+	default: {volume}% ++
+	The format for how information should be displayed.
+
+*rotate*: ++
+	typeof: integer ++
+	Positive value to rotate the text label.
+
+*max-length*: ++
+	typeof: integer ++
+	The maximum length in character the module should display.
+
+*scroll-step*: ++
+	typeof: int ++
+	default: 5 ++
+	The speed in which to change the volume when scrolling.
+
+*on-click*: ++
+	typeof: string ++
+	Command to execute when clicked on the module.
+	This replaces the default behaviour of toggling mute.
+
+*on-click-middle*: ++
+	typeof: string ++
+	Command to execute when middle-clicked on the module using mousewheel.
+
+*on-click-right*: ++
+	typeof: string ++
+	Command to execute when you right clicked on the module.
+
+*on-update*: ++
+	typeof: string ++
+	Command to execute when the module is updated.
+
+*on-scroll-up*: ++
+	typeof: string ++
+	Command to execute when scrolling up on the module.
+	This replaces the default behaviour of volume control.
+
+*on-scroll-down*: ++
+	typeof: string ++
+	Command to execute when scrolling down on the module.
+	This replaces the default behaviour of volume control.
+
+*smooth-scrolling-threshold*: ++
+	typeof: double ++
+	Threshold to be used when scrolling.
+
+# FORMAT REPLACEMENTS
+
+*{volume}*: Volume in percentage.
+
+*{raw_value}*: Volume as value reported by sndio.
+
+# EXAMPLES
+
+```
+"sndio": {
+    "format": "{raw_value} 🎜",
+    "scroll-step": 3
+}
+```
+
+# STYLE
+
+- *#sndio*
+- *#sndio.muted*