Merge pull request #34685 from cransom/fix-darwin-v8_3_16_14

v8_3_16_14: fix on darwin

pkgs/top-level/all-packages.nix

···
   v8_3_16_14 = callPackage ../development/libraries/v8/3.16.14.nix {
     inherit (python2Packages) python gyp;
     cctools = darwin.cctools;
-    stdenv = overrideCC stdenv gcc5;
+    stdenv = if stdenv.isDarwin then stdenv else overrideCC stdenv gcc5;
   };
 
   v8_6_x = callPackage ../development/libraries/v8/6_x.nix {