cc-wrapper: WIP linking hack for mac OS

Probably best to override Haskell packages set, or anything else
linking a lot of libraries, with this.

pkgs/test/macos-sierra-shared/default.nix

@@ -0,0 +1,43 @@
+{ lib, clangStdenv, clang-sierraHack-stdenv }:
+
+let
+  makeBigExe = stdenv: prefix: rec {
+
+    sillyLibs = lib.genList (i: stdenv.mkDerivation rec {
+      name = "${prefix}-fluff-${toString i}";
+      unpackPhase = ''
+        src=$PWD
+        echo 'int asdf${toString i}(void) { return ${toString i}; }' > ${name}.c
+      '';
+      buildPhase = ''
+        $CC -shared ${name}.c -o lib${name}.dylib -Wl,-install_name,$out/lib/lib${name}.dylib
+      '';
+      installPhase = ''
+        mkdir -p "$out/lib"
+        mv lib${name}.dylib "$out/lib"
+      '';
+    }) 500
+    ;
+
+    finalExe = stdenv.mkDerivation rec {
+      name = "${prefix}-final-asdf";
+      unpackPhase = ''
+        src=$PWD
+        echo 'int main(int argc, char **argv) { return argc; }' > main.c;
+      '';
+      buildPhase = ''
+        $CC main.c ${toString (map (x: "-l${x.name}") sillyLibs)} -o asdf
+      '';
+      buildInputs = sillyLibs;
+      installPhase = ''
+        mkdir -p "$out/bin"
+        mv asdf "$out/bin"
+      '';
+    };
+
+  };
+
+in {
+  good = makeBigExe clang-sierraHack-stdenv "good";
+  bad  = makeBigExe clangStdenv             "bad";
+}