libseat: init at 0.5.0

Wlroots will require libseat in the future, add the library to nixpkgs
in preparation.

pkgs/development/libraries/libseat/default.nix

@@ -0,0 +1,37 @@
+{ fetchFromSourcehut
+, lib
+, meson
+, ninja
+, pkg-config
+, stdenv
+, systemd
+}:
+
+stdenv.mkDerivation rec {
+  pname = "libseat";
+  version = "0.5.0";
+
+  src = fetchFromSourcehut {
+    owner = "~kennylevinsen";
+    repo = "seatd";
+    rev = version;
+    sha256 = "sha256-JwlJLHkRgSRqfQEhXbzuFTmhxfbwKVdLICPbTDbC9M0=";
+  };
+
+  nativeBuildInputs = [ meson ninja pkg-config ];
+
+  buildInputs = [
+    systemd
+  ];
+
+  mesonFlags = [ "-Dserver=disabled" "-Dseatd=disabled" "-Dlogind=enabled"];
+
+  meta = with lib; {
+    description = "A universal seat management library";
+    changelog   = "https://git.sr.ht/~kennylevinsen/seatd/refs/${version}";
+    homepage    = "https://sr.ht/~kennylevinsen/seatd/";
+    license     = licenses.mit;
+    platforms   = platforms.linux;
+    maintainers = with maintainers; [ emantor ];
+  };
+}

pkgs/top-level/all-packages.nix

@@ -15680,6 +15680,8 @@ in
 
   libsearpc = callPackage ../development/libraries/libsearpc { };
 
+  libseat = callPackage ../development/libraries/libseat { };
+
   libsigcxx = callPackage ../development/libraries/libsigcxx { };
 
   libsigcxx12 = callPackage ../development/libraries/libsigcxx/1.2.nix { };