fix source root locations.

These have changed following commit
c3255fe8ec.

See also:

- https://github.com/NixOS/nixpkgs/pull/31004
- https://github.com/NixOS/nixpkgs/pull/31106

pkgs/development/compilers/dmd/2.067.1.nix

@@ -17,18 +17,21 @@ stdenv.mkDerivation rec {
     repo = "dmd";
     rev = "v${version}";
     sha256 = "0fm29lg8axfmzdaj0y6vg70lhwb5d9rv4aavnvdd15xjschinlcz";
+    name = "dmd-v${version}-src";
   })
   (fetchFromGitHub {
     owner = "dlang";
     repo = "druntime";
     rev = "v${version}";
     sha256 = "1n2qfw9kmnql0fk2nxikispqs7vh85nhvyyr00fk227n9lgnqf02";
+    name = "druntime-v${version}-src";
   })
   (fetchFromGitHub {
     owner = "dlang";
     repo = "phobos";
     rev = "v${version}";
     sha256 = "0fywgds9xvjcgnqxmpwr67p3wi2m535619pvj159cgwv5y0nr3p1";
+    name = "phobos-v${version}-src";
   })
   ];
 

pkgs/development/compilers/dmd/default.nix

@@ -14,18 +14,21 @@ stdenv.mkDerivation rec {
     repo = "dmd";
     rev = "v${version}";
     sha256 = "0kq6r8rcghvzk5jcphg89l85rg734s29bssd2rcw3fygx0k9a9k5";
+    name = "dmd-v${version}-src";
   })
   (fetchFromGitHub {
     owner = "dlang";
     repo = "druntime";
     rev = "v${version}";
     sha256 = "0idn2v1lmp7hl637g3i7pdfj9mjk4sclkz4cm77nl8873k2fhk8j";
+    name = "druntime-v${version}-src";
   })
   (fetchFromGitHub {
     owner = "dlang";
     repo = "phobos";
     rev = "v${version}";
     sha256 = "1a7q5fd15yspgs5plxgx54jyrcwgzlyw3rahmz04jd2s5h56dj04";
+    name = "phobos-v${version}-src";
   })
   ];