Merge pull request #28860 from dtzWill/fix/clang_34_hardening

clang 3.4: Disable hardening bits (#28543)

pkgs/top-level/all-packages.nix

···
   clang_38 = llvmPackages_38.clang;
   clang_37 = llvmPackages_37.clang;
   clang_35 = wrapCC llvmPackages_35.clang;
-  clang_34 = wrapCC llvmPackages_34.clang;
+  clang_34 = (wrapCC llvmPackages_34.clang).override {
+    # Default cc-wrapper's hardening flags don't work with clang-3.4,
+    # so just remove it entirely for this wrapper.
+    extraBuildCommands = ''
+    :> $out/nix-support/add-hardening.sh
+    '';
+  };
 
   clang-tools = callPackage ../development/tools/clang-tools { };