gdcm: move to pkgs/by-name

this shouldn't create any rebuilds

pkgs/by-name/gd/gdcm/package.nix

@@ -6,7 +6,7 @@
   cmake,
   enableVTK ? true,
   vtk,
-  DarwinTools, # sw_vers
+  darwin, # sw_vers
   enablePython ? false,
   python ? null,
   swig,
@@ -61,7 +61,7 @@ stdenv.mkDerivation (finalAttrs: {
     cmake
     pkg-config
   ]
-  ++ lib.optional stdenv.hostPlatform.isDarwin DarwinTools;
+  ++ lib.optional stdenv.hostPlatform.isDarwin darwin.DarwinTools;
 
   buildInputs = [
     expat

pkgs/top-level/all-packages.nix

@@ -6810,10 +6810,6 @@ with pkgs;
     useMinimalFeatures = true;
   };
 
-  gdcm = callPackage ../development/libraries/gdcm {
-    inherit (darwin) DarwinTools;
-  };
-
   ghp-import = with python3Packages; toPythonApplication ghp-import;
 
   ghcid = haskellPackages.ghcid.bin;