darwin.DarwinTools: remove reference to CFPriv.h

Fixes build on aarch64-darwin.

pkgs/os-specific/darwin/DarwinTools/default.nix

@@ -8,7 +8,11 @@ stdenv.mkDerivation rec {
     sha256 = "0hh4jl590jv3v830p77r3jcrnpndy7p2b8ajai3ldpnx2913jfhp";
   };
 
-  patchPhase = ''
+  patches = [
+    ./sw_vers-CFPriv.patch
+  ];
+
+  postPatch = ''
     substituteInPlace Makefile \
       --replace gcc cc
   '';

pkgs/os-specific/darwin/DarwinTools/sw_vers-CFPriv.patch

@@ -0,0 +1,19 @@
+--- a/sw_vers.c	2021-04-19 13:06:50.131346864 +0900
++++ b/sw_vers.c	2021-04-19 13:07:32.481967474 +0900
+@@ -28,7 +28,15 @@
+  */
+ 
+ #include <CoreFoundation/CoreFoundation.h>
+-#include <CoreFoundation/CFPriv.h>
++
++// Avoid dependency on CoreFoundation/CFPriv, which no longer appears to be
++// part of the upstream sdk.
++
++CFDictionaryRef _CFCopyServerVersionDictionary(void);
++CFDictionaryRef _CFCopySystemVersionDictionary(void);
++extern CFStringRef _kCFSystemVersionProductNameKey;
++extern CFStringRef _kCFSystemVersionProductVersionKey;
++extern CFStringRef _kCFSystemVersionBuildVersionKey;
+ 
+ void usage(char *progname) {
+ 	fprintf(stderr, "Usage: %s [-productName|-productVersion|-buildVersion]\n", progname);