darwin.libmalloc: remove and replace with stubs

pkgs/os-specific/darwin/apple-source-releases/default.nix

@@ -262,9 +262,6 @@ developerToolsPackages_11_3_1 // macosPackages_11_0_1 // {
     AvailabilityVersions = callPackage ./AvailabilityVersions/package.nix { };
     copyfile        = callPackage ./copyfile/package.nix { };
     Csu             = callPackage ./Csu/package.nix { };
-    libmalloc       = if isSdk10_12 then
-      applePackage "libmalloc" "osx-10.12.6" "sha256-brfG4GEF2yZipKdhlPq6DhT2z5hKYSb2MAmffaikdO4=" {}
-    else macosPackages_11_0_1.libmalloc;
     libplatform     = if isSdk10_12 then
       applePackage "libplatform"       "osx-10.12.6"     "sha256-6McMTjw55xtnCsFI3AB1osRagnuB5pSTqeMKD3gpGtM=" {}
     else macosPackages_11_0_1.libplatform;

pkgs/os-specific/darwin/apple-source-releases/libmalloc/default.nix

@@ -1,10 +0,0 @@
-{ appleDerivation', stdenvNoCC }:
-
-# Unfortunately, buiding libmalloc is not feasible due to its use of non-public headers, but its
-# headers are needed by Libsystem.
-appleDerivation' stdenvNoCC {
-  installPhase = ''
-    mkdir -p $out/include
-    cp -R include/malloc $out/include/
-  '';
-}

pkgs/os-specific/darwin/apple-source-releases/macos-11.0.1.nix

@@ -12,7 +12,6 @@ bootstrap_cmds = callPackage ./bootstrap_cmds/package.nix { };
 copyfile = applePackage' "copyfile" "173.40.2" "macos-11.0.1" "1j20909inn2iw8n51b8vk551wznfi3bhfziy8nbv08qj5lk50m04" {};
 diskdev_cmds = applePackage' "diskdev_cmds" "667.40.1" "macos-11.0.1" "0wr60vyvgkbc4wyldnsqas0xss2k1fgmbdk3vnhj6v6jqa98l1ny" {};
 file_cmds = applePackage' "file_cmds" "321.40.3" "macos-11.0.1" "0p077lnbcy8266m03a0fssj4214bjxh88y3qkspnzcvi0g84k43q" {};
-libmalloc = applePackage' "libmalloc" "317.40.8" "macos-11.0.1" "sha256-Tdhb0mq3w4Hwvp3xHB79Vr22hCOQK6h28HCsd7jvITI=" {};
 libplatform = applePackage' "libplatform" "254.40.4" "macos-11.0.1" "1qf3ri0yd8b1xjln1j1gyx7ks6k3a2jhd63blyvfby75y9s7flky" {};
 libpthread = applePackage' "libpthread" "454.40.3" "macos-11.0.1" "0zljbw8mpb80n1if65hhi9lkgwbgjr8vc9wvf7q1nl3mzyl35f8p" {};
 libresolv = applePackage' "libresolv" "68" "macos-11.0.1" "045ahh8nvaam9whryc2f5g5xagwp7d187r80kcff82snp5p66aq1" {};

pkgs/top-level/darwin-packages.nix

@@ -93,6 +93,7 @@ makeScopeWithSplicing' {
     "launchd"
     "libclosure"
     "libdispatch"
+    "libmalloc"
   ] (mkStub apple_sdk.version);
 in
 impure-cmds // appleSourcePackages // stubs // {