cctools: Add alternative source for sierra hack

Source master rebase of my [PR #34].

Eventually, we might consider doing something for GNU binutils too, in
order that we switch (the normal) ld-wrapper to always use this to
leverage ld to resolve libraries, rather than faking it in bash.

[PR #34]: https://github.com/tpoechtrager/cctools-port/pull/34

pkgs/os-specific/darwin/cctools/port.nix

@@ -2,6 +2,7 @@
 , llvm, libcxx, libcxxabi, clang, libuuid
 , libobjc ? null, maloader ? null, xctoolchain ? null
 , hostPlatform, targetPlatform
+, enableDumpNormalizedLibArgs ? false
 }:
 
 let
@@ -20,12 +21,18 @@ let
     name = "${targetPrefix}cctools-port-${version}";
     version = "895";
 
-    src = fetchFromGitHub {
+    src = fetchFromGitHub (if enableDumpNormalizedLibArgs then {
+      owner  = "tpoechtrager";
+      repo   = "cctools-port";
+      # master with https://github.com/tpoechtrager/cctools-port/pull/34
+      rev    = "8395d4b2c3350356e2fb02f5e04f4f463c7388df";
+      sha256 = "10vbf1cfzx02q8chc77s84fp2kydjpx2y682mr6mrbb7sq5rwh8f";
+    } else {
       owner  = "tpoechtrager";
       repo   = "cctools-port";
       rev    = "2e569d765440b8cd6414a695637617521aa2375b"; # From branch 895-ld64-274.2
       sha256 = "0l45mvyags56jfi24rawms8j2ihbc45mq7v13pkrrwppghqrdn52";
-    };
+    });
 
     outputs = [ "out" "dev" ];
 

pkgs/top-level/all-packages.nix

@@ -5779,8 +5779,13 @@ with pkgs;
 
   clang-sierraHack = clang.override {
     name = "clang-wrapper-with-reexport-hack";
-    bintools = clang.bintools.override {
+    bintools = darwin.binutils.override {
       useMacosReexportHack = true;
+      bintools = darwin.binutils.bintools.override {
+        cctools = darwin.cctools.override {
+          enableDumpNormalizedLibArgs = true;
+        };
+      };
     };
   };