libsForQt5.qmltermwidget: Minor cleanups

- Clarify license
- Replace INSTALL_ROOT with proper $$PREFIX usage
- Minor style stuff

pkgs/development/libraries/qmltermwidget/default.nix

@@ -1,9 +1,9 @@
 { lib
 , stdenv
 , fetchFromGitHub
+, qmake
 , qtbase
 , qtquick1
-, qmake
 , qtmultimedia
 , utmp
 }:
@@ -13,13 +13,15 @@ stdenv.mkDerivation {
   version = "unstable-2022-01-09";
 
   src = fetchFromGitHub {
-    repo = "qmltermwidget";
     owner = "Swordfish90";
+    repo = "qmltermwidget";
     rev = "63228027e1f97c24abb907550b22ee91836929c5";
     hash = "sha256-aVaiRpkYvuyomdkQYAgjIfi6a3wG2a6hNH1CfkA2WKQ=";
   };
 
-  nativeBuildInputs = [ qmake ];
+  nativeBuildInputs = [
+    qmake
+  ];
 
   buildInputs = [
     qtbase
@@ -34,17 +36,15 @@ stdenv.mkDerivation {
 
   postPatch = ''
     substituteInPlace qmltermwidget.pro \
-      --replace '$$[QT_INSTALL_QML]' "/$qtQmlPrefix/"
+      --replace '$$[QT_INSTALL_QML]' '$$PREFIX/${qtbase.qtQmlPrefix}/'
   '';
 
-  installFlags = [ "INSTALL_ROOT=${placeholder "out"}" ];
-
   dontWrapQtApps = true;
 
   meta = {
     description = "A QML port of qtermwidget";
     homepage = "https://github.com/Swordfish90/qmltermwidget";
-    license = lib.licenses.gpl2;
+    license = lib.licenses.gpl2Plus;
     platforms = with lib.platforms; linux ++ darwin;
     maintainers = with lib.maintainers; [ OPNA2608 ];
   };