--- Libc/Libc-825.24/xcodescripts/generate_features.pl
+++ Libc/Libc-1669.0.4/xcodescripts/generate_features.pl
@@ -1,8 +1,4 @@
 #!/usr/bin/perl
-
-if ($ENV{"ACTION"} eq "installhdrs") {
-	exit 0;
-}
 
 # Generates the libc-features.h files used to control #ifdef behaviour in Libc
 use warnings;
@@ -23,15 +19,19 @@
 {
 	# set ENV{"CURRENT_ARCH"} so we can predicate on it
 	$ENV{"CURRENT_ARCH"} = $arch;
-	
-	my $platformName = $ENV{"PLATFORM_NAME"};
-	$platformName = "iphoneos" if ($platformName eq "iphonesimulator");
-
+
+	my $platformName = $ENV{"VARIANT_PLATFORM_NAME"};
+	$platformName =~ s/simulator/os/;
+
+	# Try to find a platform+arch config file. If not found, try just
+	# a platform config file.
+	my $platformArchPath = $ENV{"SRCROOT"} . "/Platforms/" . $platformName . "/Makefile." . $arch . ".inc";
 	my $platformPath = $ENV{"SRCROOT"} . "/Platforms/" . $platformName . "/Makefile.inc";
+
 	my $featuresHeaderDir = $ENV{"DERIVED_FILES_DIR"}."/".$arch;
 	my $featuresHeader = $featuresHeaderDir."/libc-features.h";
 
-	open FEATURESFILE, "<$platformPath" or die "Unable to open: $platformPath";
+	open FEATURESFILE, "<$platformArchPath" or open FEATURESFILE, "<$platformPath" or die "Unable to open: $platformArchPath nor $platformPath";
 
 	my %features = ();
 	my $skip = 0;
@@ -51,7 +51,7 @@
 			my $regex = $2;
 			
 			$nested++;
-			if ($ENV{$envvar} !~ /$regex/) {
+			if (!defined($ENV{$envvar}) || ($ENV{$envvar} !~ /$regex/)) {
 				$skip += 1;
 			}
 		}
@@ -80,10 +80,11 @@
 	elsif ($unifdef == 1) {
 		# assume FEATURE_BLOCKS was on by default
 		$unifdefs{"UNIFDEF_BLOCKS"} = 1;
+		$unifdefs{"UNIFDEF_DRIVERKIT"} = defined($ENV{"DRIVERKITSDK"});
 		$unifdefs{"UNIFDEF_LEGACY_64_APIS"} = defined($features{"FEATURE_LEGACY_64_APIS"});
 		$unifdefs{"UNIFDEF_LEGACY_RUNE_APIS"} = defined($features{"FEATURE_LEGACY_RUNE_APIS"});
 		$unifdefs{"UNIFDEF_LEGACY_UTMP_APIS"} = defined($features{"FEATURE_LEGACY_UTMP_APIS"});
-		$unifdefs{"UNIFDEF_MOVE_LOCALTIME"} = defined($features{"FEATURE_MOVE_LOCALTIME"});
+		$unifdefs{"UNIFDEF_POSIX_ILP32_ALLOW"} = defined($features{"FEATURE_POSIX_ILP32_ALLOW"});
 		
 		my $output = "";
 		for my $d (keys %unifdefs) {
@@ -97,10 +98,14 @@
 	
 	elsif ($unifdef == 0) {
 		# If we touch this file on every build, then every other iterative build in Xcode will rebuild *everything*
-		my $platform_mtime = (stat($platformPath))[9];
+		my $platform_mtime = (stat($platformArchPath))[9];
+		if (!defined($platform_mtime)) {
+			# try the other one
+			$platform_mtime = (stat($platformPath))[9];
+		}
 		my $header_mtime = (stat($featuresHeader))[9];
 
-		if ($header_mtime > $platform_mtime) {
+		if (defined($header_mtime) && defined($platform_mtime) && ($header_mtime > $platform_mtime)) {
 			exit 0;
 		}
 
@@ -123,6 +128,9 @@
 		my $shortarch = $arch;
 		$shortarch =~ s/armv\d+[a-z]?/arm/g;
 
+		# map all arm64 subtypes to arm64
+		$shortarch =~ s/arm64[_a-z0-9]*/arm64/g;
+
 		printf HEADER "#if !defined(__".$shortarch."__)\n";
 		printf HEADER "#error Mismatched libc-features.h architecture\n";
 		printf HEADER "#endif\n\n";
@@ -143,12 +151,6 @@
 			printf HEADER "#define UNIFDEF_LEGACY_UTMP_APIS 1\n";
 		} else {
 			printf HEADER "/* #undef UNIFDEF_LEGACY_UTMP_APIS */\n";
-		}
-
-		if (defined($features{"FEATURE_MOVE_LOCALTIME"})) {
-			printf HEADER "#define UNIFDEF_MOVE_LOCALTIME 1\n";
-		} else {
-			printf HEADER "/* #undef UNIFDEF_MOVE_LOCALTIME */\n";
 		}
 
 		if (defined($features{"FEATURE_ONLY_1050_VARIANTS"})) {
@@ -187,12 +189,6 @@
 			printf HEADER "/* #undef __APPLE_PR3417676_HACK__ */\n";
 		}
 
-		if (defined($features{"FEATURE_PATCH_5243343"})) {
-			printf HEADER "#define PR_5243343 1\n";
-		} else {
-			printf HEADER "/* #undef PR_5243343 */\n";
-		}
-
 		if (defined($features{"FEATURE_PLOCKSTAT"})) {
 			printf HEADER "#define PLOCKSTAT 1\n";
 		} else {
@@ -205,16 +201,22 @@
 			printf HEADER "/* #undef NOTIFY_TZ */\n";
 		}
 
-		if (defined($features{"FEATURE_NO_LIBCRASHREPORTERCLIENT"})) {
-			printf HEADER "#define LIBC_NO_LIBCRASHREPORTERCLIENT 1\n";
-		} else {
-			printf HEADER "/* #undef LIBC_NO_LIBCRASHREPORTERCLIENT */\n";
-		}
-
-		if (defined($features{"FEATURE_MEMORYSTATUS"})) {
-			printf HEADER "#define CONFIG_MEMORYSTATUS 1\n";
-		} else {
-			printf HEADER "/* #undef CONFIG_MEMORYSTATUS */\n";
+		if (defined($features{"FEATURE_SMALL_STDIOBUF"})) {
+			printf HEADER "#define FEATURE_SMALL_STDIOBUF 1\n";
+		} else {
+			printf HEADER "/* #undef FEATURE_SMALL_STDIOBUF */\n";
+		}
+
+		if (defined($features{"FEATURE_XPRINTF_PERF"})) {
+			printf HEADER "#define XPRINTF_PERF 1\n";
+		} else {
+			printf HEADER "/* #undef XPRINTF_PERF */\n";
+		}
+
+		if (defined($features{"FEATURE_SIGNAL_RESTRICTION"})) {
+			printf HEADER "#define FEATURE_SIGNAL_RESTRICTION 1\n";
+		} else {
+			printf HEADER "/* #undef FEATURE_SIGNAL_RESTRICTION */\n";
 		}
 
 		printf HEADER "#endif // _LIBC_FEATURES_H_\n";