lib.licenses: replace qwt with qwtException

lib/licenses.nix

@@ -1170,9 +1170,9 @@ lib.mapAttrs mkLicense (
       fullName = "Q Public License 1.0";
     };
 
-    qwt = {
-      fullName = "Qwt License, Version 1.0";
-      url = "https://qwt.sourceforge.io/qwtlicense.html";
+    qwtException = {
+      spdxId = "Qwt-exception-1.0";
+      fullName = "Qwt exception 1.0";
     };
 
     ruby = {

pkgs/development/libraries/qwt/6_1.nix

@@ -36,7 +36,10 @@ stdenv.mkDerivation rec {
     description = "Qt widgets for technical applications";
     homepage = "http://qwt.sourceforge.net/";
     # LGPL 2.1 plus a few exceptions (more liberal)
-    license = licenses.qwt;
+    license = with lib.licenses; [
+      lgpl21Only
+      qwtException
+    ];
     platforms = platforms.unix;
     maintainers = [ maintainers.bjornfor ];
   };

pkgs/development/libraries/qwt/default.nix

@@ -42,7 +42,10 @@ stdenv.mkDerivation rec {
     description = "Qt widgets for technical applications";
     homepage = "http://qwt.sourceforge.net/";
     # LGPL 2.1 plus a few exceptions (more liberal)
-    license = lib.licenses.qwt;
+    license = with lib.licenses; [
+      lgpl21Only
+      qwtException
+    ];
     platforms = platforms.unix;
     maintainers = [ maintainers.bjornfor ];
   };