Libsystem: get os/{log,trace,activity}.h from darling

This is the only place I can find the headers.

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

@@ -1,7 +1,7 @@
 { stdenv, appleDerivation, cpio, xnu, Libc, Libm, libdispatch, cctools, Libinfo
 , dyld, Csu, architecture, libclosure, CarbonHeaders, ncurses, CommonCrypto
 , copyfile, removefile, libresolv, Libnotify, libplatform, libpthread
-, mDNSResponder, launchd, libutil, hfs }:
+, mDNSResponder, launchd, libutil, hfs, darling }:
 
 appleDerivation rec {
   dontBuild = true;
@@ -30,6 +30,11 @@ appleDerivation rec {
     (cd ${cctools.dev}/include/mach-o && find . -name '*.h' | cpio -pdm $out/include/mach-o)
 
     mkdir -p $out/include/os
+
+    cp ${darling.src}/src/libc/os/activity.h $out/include/os
+    cp ${darling.src}/src/libc/os/log.h $out/include/os
+    cp ${darling.src}/src/duct/include/os/trace.h $out/include/os
+
     cat <<EOF > $out/include/os/availability.h
     #ifndef __OS_AVAILABILITY__
     #define __OS_AVAILABILITY__

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

@@ -114,8 +114,6 @@ appleDerivation ({
     # Get rid of some junk lying around
     rm -rf $out/internal_hdr $out/usr $out/local
 
-    mv $out/include/libkern/os/log.h $out/include/os/log.h
-
     # Add some symlinks
     ln -s $out/Library/Frameworks/System.framework/Versions/B \
           $out/Library/Frameworks/System.framework/Versions/Current