icu66: init at 66.1

pkgs/development/libraries/icu/66.nix

···
+import ./base.nix {
+  version = "66.1";
+  sha256 = "0bharwzc9nzkbrcf405z2nb3h7q0711z450arz0mjmdrk8hg58sj";
+}

pkgs/top-level/all-packages.nix

···
   } // (stdenv.lib.optionalAttrs (stdenv.hostPlatform.isi686 && stdenv.cc.isGNU) {
       stdenv = gcc6Stdenv; # with gcc-7: undefined reference to `__divmoddi4'
     }));
+  icu66 = callPackage ../development/libraries/icu/66.nix ({
+    nativeBuildRoot = buildPackages.icu66.override { buildRootOnly = true; };
+  } // (stdenv.lib.optionalAttrs (stdenv.hostPlatform.isi686 && stdenv.cc.isGNU) {
+      stdenv = gcc6Stdenv; # with gcc-7: undefined reference to `__divmoddi4'
+    }));
 
   icu = icu64;