darwin.libSystem: cleanup

We don’t want to rely on a certain output so just use ‘getDev’ so Nix
will choose the right output for us.

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

@@ -7,6 +7,13 @@ appleDerivation rec {
 
   outputs = [ "out" "dev" ];
 
+  bundledHeaders = map stdenv.lib.getDev [ Libc Libm Libinfo dyld architecture
+                                           libclosure CarbonHeaders libdispatch
+                                           ncurses CommonCrypto copyfile
+                                           removefile libresolv Libnotify
+                                           libplatform mDNSResponder launchd
+                                           libutil libpthread ];
+
   installPhase = ''
     export NIX_ENFORCE_PURITY=
 
@@ -17,9 +24,7 @@ appleDerivation rec {
     cp ${xnu}/Library/Frameworks/Kernel.framework/Versions/A/Headers/Availability*.h $out/include
     cp ${xnu}/Library/Frameworks/Kernel.framework/Versions/A/Headers/stdarg.h        $out/include
 
-    for dep in ${Libc} ${Libm} ${Libinfo} ${dyld} ${architecture} ${libclosure} ${CarbonHeaders} \
-               ${libdispatch} ${ncurses.dev} ${CommonCrypto} ${copyfile} ${removefile} ${libresolv} \
-               ${Libnotify} ${libplatform} ${mDNSResponder} ${launchd} ${libutil} ${libpthread}; do
+    for dep in $bundledHeaders; do
       (cd $dep/include && find . -name '*.h' | cpio -pdm $out/include)
     done