uget: remove null references, uget-integrator: use installShellFiles (#406261)

pkgs/by-name/ug/uget-integrator/package.nix

@@ -4,6 +4,7 @@
   fetchFromGitHub,
   uget,
   python3Packages,
+  installShellFiles,
 }:
 
 stdenv.mkDerivation rec {
@@ -17,7 +18,10 @@ stdenv.mkDerivation rec {
     sha256 = "0bfqwbpprxp5sy49p2hqcjdfj7zamnp2hhcnnyccffkn7pghx8pp";
   };
 
-  nativeBuildInputs = [ python3Packages.wrapPython ];
+  nativeBuildInputs = [
+    installShellFiles
+    python3Packages.wrapPython
+  ];
 
   buildInputs = [
     uget
@@ -29,7 +33,7 @@ stdenv.mkDerivation rec {
       substituteInPlace $f --replace "/usr" "$out"
     done
 
-    install -D -t $out/bin                                   bin/uget-integrator
+    installBin bin/uget-integrator
     install -D -t $out/etc/opt/chrome/native-messaging-hosts conf/com.ugetdm.chrome.json
     install -D -t $out/etc/chromium/native-messaging-hosts   conf/com.ugetdm.chrome.json
     install -D -t $out/etc/opera/native-messaging-hosts      conf/com.ugetdm.chrome.json

pkgs/by-name/ug/uget/package.nix

@@ -12,7 +12,9 @@
   gtk3,
   dconf,
   wrapGAppsHook3,
-  aria2 ? null,
+  aria2,
+  # Boolean guards
+  aria2Support ? true,
 }:
 
 stdenv.mkDerivation rec {
@@ -51,13 +53,11 @@ stdenv.mkDerivation rec {
       gst-plugins-base
       gst-plugins-good
     ])
-    ++ (lib.optional (aria2 != null) aria2);
+    ++ (lib.optional aria2Support aria2);
 
   enableParallelBuilding = true;
 
-  preFixup = lib.optionalString (
-    aria2 != null
-  ) ''gappsWrapperArgs+=(--suffix PATH : "${aria2}/bin")'';
+  preFixup = lib.optionalString aria2Support ''gappsWrapperArgs+=(--suffix PATH : "${aria2}/bin")'';
 
   meta = with lib; {
     description = "Download manager using GTK and libcurl";