gnu: Add swayidle.

* gnu/packages/wm.scm (swayidle): New variable.

gnu/packages/wm.scm

@@ -1198,3 +1198,26 @@ modules for building a Wayland compositor.")
     (synopsis "Wayland compositor compatible with i3")
     (description "Sway is a i3-compatible Wayland compositor.")
     (license license:expat)))       ; MIT license
+
+(define-public swayidle
+  (package
+    (name "swayidle")
+    (version "1.2")
+    (source
+     (origin
+       (method git-fetch)
+       (uri (git-reference
+             (url "https://github.com/swaywm/swayidle.git")
+             (commit version)))
+       (file-name (git-file-name name version))
+       (sha256
+        (base32 "0b65flajwn2i6k2kdxxgw25w7ikzzmm595f4j5x1wac1rb0yah9w"))))
+    (build-system meson-build-system)
+    (inputs `(("wayland" ,wayland)))
+    (native-inputs `(("pkg-config" ,pkg-config)
+                     ("scdoc" ,scdoc)
+                     ("wayland-protocols" ,wayland-protocols)))
+    (home-page "https://github.com/swaywm/sway")
+    (synopsis "Idle management daemon for Wayland compositors")
+    (description "Swayidle is a idle management daemon for Wayland compositors.")
+    (license license:expat))) ; MIT license