xnu: Fix python3 patch

This reverts 7da313e10a because it's no
longer necessary.

pkgs/os-specific/darwin/apple-source-releases/xnu/python3.patch

@@ -18,7 +18,7 @@ index 73b2db4..d354ba0 100755
 -	m = id_name_pattern.match(line)
 -	if m:
 +        m = id_name_pattern.match(line)
-+    if m:
++        if m:
              code_table += [(int(m.group(1),base=16), m.group(2))]
  
  # emit typedef:

pkgs/stdenv/darwin/make-bootstrap-tools.nix

@@ -33,10 +33,7 @@ in rec {
   curl_ = curlMinimal.override (args: { gssSupport = false; http2Support = false; });
 
   # Avoid stdenv rebuild.
-  Libsystem_ = (darwin.Libsystem.override (args:
-    { xnu = darwin.xnu.overrideAttrs (oldAttrs:
-      { patches = [ ./fixed-xnu-python3.patch ]; });
-    })).overrideAttrs (oldAttrs:
+  Libsystem_ = darwin.Libsystem.overrideAttrs (oldAttrs:
     { installPhase = oldAttrs.installPhase + ''
         cat <<EOF > $out/include/TargetConditionals.h
         #ifndef __TARGETCONDITIONALS__