Add support for NDK r23.

Context: https://github.com/android/ndk/wiki/Changelog-r23#changelog

The most important changes for Xamarin.Android:

NDK r23 removes GNU Binutils and so we need to switch to using our
bundled copy of them.

Upstream changes:

* Includes Android 12 APIs.
* Updated LLVM to clang-r416183b, based on LLVM 12 development.
  * [Issue 1047]: Fixes crash when using ASan with the CFI unwinder.
  * [Issue 1096]: Includes support for [Polly]. Enable by adding `-mllvm -polly`
    to your cflags.
  * [Issue 1230]: LLVM's libunwind is now used instead of libgcc for all
    architectures rather than just 32-bit Arm.
  * [Issue 1231]: LLVM's libclang_rt.builtins is now used instead of libgcc.
  * [Issue 1406]: Fixes crash with Neon intrinsic.
* Vulkan validation layer source and binaries are no longer shipped in the NDK.
  The latest are now posted directly to [GitHub](https://github.com/KhronosGroup/Vulkan-ValidationLayers/releases).
* Vulkan tools source is also removed, specifically vulkan_wrapper.
  It should be downloaded upstream from [GitHub](https://github.com/KhronosGroup/Vulkan-Tools).
* The toolchain file (android.toolchain.cmake) is refactored to base on CMake's
  integrated Android support. This new toolchain file will be enabled by default
  for CMake 3.21 and newer. No user side change is expected. But if anything goes
  wrong, please file a bug and set `ANDROID_USE_LEGACY_TOOLCHAIN_FILE=ON` to
  restore the legacy behavior.
    * When using the new behavior (when using CMake 3.21+ and not explicitly
      selecting the legacy toolchain), **default build flags may change**. One
      of the primary goals was to reduce the behavior differences between our
      toolchain and CMake, and CMake's default flags do not always match the
      legacy toolchain file. Most notably, if using `CMAKE_BUILD_TYPE=Release`,
      your optimization type will likely be `-O3` instead of `-O2` or `-Oz`. See
      [Issue 1536] for more information.
* [Issue 929]: `find_library` now prefers shared libraries from the sysroot over
  static libraries.
* [Issue 1390]: ndk-build now warns when building a static executable with the
  wrong API level.
* [Issue 1452]: `NDK_ANALYZE=1` now sets `APP_CLANG_TIDY=true` rather than using
  scan-build. clang-tidy performs all the same checks by default, and scan-build
  was no longer working. See the bug for more details, but no user-side changes
  should be needed.

[Issue 929]: android/ndk#929
[Issue 1047]: android/ndk#1047
[Issue 1096]: android/ndk#1096
[Issue 1230]: android/ndk#1230
[Issue 1231]: android/ndk#1231
[Issue 1390]: android/ndk#1390
[Issue 1406]: android/ndk#1406
[Issue 1452]: android/ndk#1452
[Issue 1536]: android/ndk#1536
[Polly]: https://polly.llvm.org/

Documentation/guides/building-apps/build-properties.md

@@ -129,14 +129,14 @@ Added in Xamarin.Android 6.1.
 
 A path to a directory containing
 the Android [binutils][binutils] such as `ld`, the native linker,
-and `as`, the native assembler. These tools are part of the Android
-NDK and are also included in the Xamarin.Android installation.
+and `as`, the native assembler. These tools are included in the
+Xamarin.Android installation.
 
-The default value is `$(MonoAndroidBinDirectory)\ndk\`.
+The default value is `$(MonoAndroidBinDirectory)\binutils\`.
 
 Added in Xamarin.Android 10.0.
 
-[binutils]: https://android.googlesource.com/toolchain/binutils/
+[binutils]: https://github.com/xamarin/xamarin-android-binutils/
 
 ## AndroidBoundExceptionType
 

build-tools/installers/create-installers.targets

@@ -310,18 +310,18 @@
     <_MSBuildFilesWin Include="$(MSBuildSrcDir)\lib64\libZipSharpNative.pdb" />
     <_MSBuildFilesWin Include="$(MSBuildSrcDir)\proguard\bin\proguard.bat" />
     <_MSBuildFilesWin Include="$(MSBuildSrcDir)\aapt2.exe" />
-    <_MSBuildFilesWin Include="$(MSBuildSrcDir)\ndk\aarch64-linux-android-as.exe" />
-    <_MSBuildFilesWin Include="$(MSBuildSrcDir)\ndk\aarch64-linux-android-ld.exe" />
-    <_MSBuildFilesWin Include="$(MSBuildSrcDir)\ndk\aarch64-linux-android-strip.exe" />
-    <_MSBuildFilesWin Include="$(MSBuildSrcDir)\ndk\arm-linux-androideabi-as.exe" />
-    <_MSBuildFilesWin Include="$(MSBuildSrcDir)\ndk\arm-linux-androideabi-ld.exe" />
-    <_MSBuildFilesWin Include="$(MSBuildSrcDir)\ndk\arm-linux-androideabi-strip.exe" />
-    <_MSBuildFilesWin Include="$(MSBuildSrcDir)\ndk\i686-linux-android-as.exe" />
-    <_MSBuildFilesWin Include="$(MSBuildSrcDir)\ndk\i686-linux-android-ld.exe" />
-    <_MSBuildFilesWin Include="$(MSBuildSrcDir)\ndk\i686-linux-android-strip.exe" />
-    <_MSBuildFilesWin Include="$(MSBuildSrcDir)\ndk\x86_64-linux-android-as.exe" />
-    <_MSBuildFilesWin Include="$(MSBuildSrcDir)\ndk\x86_64-linux-android-ld.exe" />
-    <_MSBuildFilesWin Include="$(MSBuildSrcDir)\ndk\x86_64-linux-android-strip.exe" />
+    <_MSBuildFilesWin Include="$(MSBuildSrcDir)\binutils\aarch64-linux-android-as.exe" />
+    <_MSBuildFilesWin Include="$(MSBuildSrcDir)\binutils\aarch64-linux-android-ld.exe" />
+    <_MSBuildFilesWin Include="$(MSBuildSrcDir)\binutils\aarch64-linux-android-strip.exe" />
+    <_MSBuildFilesWin Include="$(MSBuildSrcDir)\binutils\arm-linux-androideabi-as.exe" />
+    <_MSBuildFilesWin Include="$(MSBuildSrcDir)\binutils\arm-linux-androideabi-ld.exe" />
+    <_MSBuildFilesWin Include="$(MSBuildSrcDir)\binutils\arm-linux-androideabi-strip.exe" />
+    <_MSBuildFilesWin Include="$(MSBuildSrcDir)\binutils\i686-linux-android-as.exe" />
+    <_MSBuildFilesWin Include="$(MSBuildSrcDir)\binutils\i686-linux-android-ld.exe" />
+    <_MSBuildFilesWin Include="$(MSBuildSrcDir)\binutils\i686-linux-android-strip.exe" />
+    <_MSBuildFilesWin Include="$(MSBuildSrcDir)\binutils\x86_64-linux-android-as.exe" />
+    <_MSBuildFilesWin Include="$(MSBuildSrcDir)\binutils\x86_64-linux-android-ld.exe" />
+    <_MSBuildFilesWin Include="$(MSBuildSrcDir)\binutils\x86_64-linux-android-strip.exe" />
     <_MSBuildLibHostFilesWin Include="$(MSBuildSrcDir)\lib\host-mxe-Win64\libmono-android.debug.dll"   Condition=" '$(HostOS)' != 'Windows' " />
     <_MSBuildLibHostFilesWin Include="$(MSBuildSrcDir)\lib\host-mxe-Win64\libmono-android.release.dll" Condition=" '$(HostOS)' != 'Windows' " />
     <_MSBuildLibHostFilesWin Include="$(MSBuildSrcDir)\lib\host-mxe-Win64\libMonoPosixHelper.dll" />
@@ -341,18 +341,18 @@
     </_MSBuildFilesUnixSignAndHarden>
   </ItemDefinitionGroup>
   <ItemGroup>
-    <_MSBuildFilesUnixSignAndHarden Include="$(MSBuildSrcDir)\$(HostOS)\ndk\aarch64-linux-android-as" />
-    <_MSBuildFilesUnixSignAndHarden Include="$(MSBuildSrcDir)\$(HostOS)\ndk\aarch64-linux-android-ld" />
-    <_MSBuildFilesUnixSignAndHarden Include="$(MSBuildSrcDir)\$(HostOS)\ndk\aarch64-linux-android-strip" />
-    <_MSBuildFilesUnixSignAndHarden Include="$(MSBuildSrcDir)\$(HostOS)\ndk\arm-linux-androideabi-as" />
-    <_MSBuildFilesUnixSignAndHarden Include="$(MSBuildSrcDir)\$(HostOS)\ndk\arm-linux-androideabi-ld" />
-    <_MSBuildFilesUnixSignAndHarden Include="$(MSBuildSrcDir)\$(HostOS)\ndk\arm-linux-androideabi-strip" />
-    <_MSBuildFilesUnixSignAndHarden Include="$(MSBuildSrcDir)\$(HostOS)\ndk\i686-linux-android-as" />
-    <_MSBuildFilesUnixSignAndHarden Include="$(MSBuildSrcDir)\$(HostOS)\ndk\i686-linux-android-ld" />
-    <_MSBuildFilesUnixSignAndHarden Include="$(MSBuildSrcDir)\$(HostOS)\ndk\i686-linux-android-strip" />
-    <_MSBuildFilesUnixSignAndHarden Include="$(MSBuildSrcDir)\$(HostOS)\ndk\x86_64-linux-android-as" />
-    <_MSBuildFilesUnixSignAndHarden Include="$(MSBuildSrcDir)\$(HostOS)\ndk\x86_64-linux-android-ld" />
-    <_MSBuildFilesUnixSignAndHarden Include="$(MSBuildSrcDir)\$(HostOS)\ndk\x86_64-linux-android-strip" />
+    <_MSBuildFilesUnixSignAndHarden Include="$(MSBuildSrcDir)\$(HostOS)\binutils\aarch64-linux-android-as" />
+    <_MSBuildFilesUnixSignAndHarden Include="$(MSBuildSrcDir)\$(HostOS)\binutils\aarch64-linux-android-ld" />
+    <_MSBuildFilesUnixSignAndHarden Include="$(MSBuildSrcDir)\$(HostOS)\binutils\aarch64-linux-android-strip" />
+    <_MSBuildFilesUnixSignAndHarden Include="$(MSBuildSrcDir)\$(HostOS)\binutils\arm-linux-androideabi-as" />
+    <_MSBuildFilesUnixSignAndHarden Include="$(MSBuildSrcDir)\$(HostOS)\binutils\arm-linux-androideabi-ld" />
+    <_MSBuildFilesUnixSignAndHarden Include="$(MSBuildSrcDir)\$(HostOS)\binutils\arm-linux-androideabi-strip" />
+    <_MSBuildFilesUnixSignAndHarden Include="$(MSBuildSrcDir)\$(HostOS)\binutils\i686-linux-android-as" />
+    <_MSBuildFilesUnixSignAndHarden Include="$(MSBuildSrcDir)\$(HostOS)\binutils\i686-linux-android-ld" />
+    <_MSBuildFilesUnixSignAndHarden Include="$(MSBuildSrcDir)\$(HostOS)\binutils\i686-linux-android-strip" />
+    <_MSBuildFilesUnixSignAndHarden Include="$(MSBuildSrcDir)\$(HostOS)\binutils\x86_64-linux-android-as" />
+    <_MSBuildFilesUnixSignAndHarden Include="$(MSBuildSrcDir)\$(HostOS)\binutils\x86_64-linux-android-ld" />
+    <_MSBuildFilesUnixSignAndHarden Include="$(MSBuildSrcDir)\$(HostOS)\binutils\x86_64-linux-android-strip" />
     <_MSBuildFilesUnix Include="$(MSBuildSrcDir)\$(HostOS)\illinkanalyzer" Permission="755" />
     <_MSBuildFilesUnix Include="$(MSBuildSrcDir)\$(HostOS)\jit-times" Permission="755" />
     <_MSBuildFilesUnix Include="$(MSBuildSrcDir)\$(HostOS)\aprofutil" ExcludeFromAndroidNETSdk="true" />

build-tools/xaprepare/xaprepare/Application/BuildInfo.cs

@@ -18,6 +18,7 @@ partial class BuildInfo : AppObject
 		public string NDKVersionMajor        { get; private set; } = String.Empty;
 		public string NDKVersionMinor        { get; private set; } = String.Empty;
 		public string NDKVersionMicro        { get; private set; } = String.Empty;
+		public string NDKVersionTag          { get; private set; } = String.Empty;
 		public string NDKMinimumApiAvailable { get; private set; } = String.Empty;
 
 		public string VersionHash            { get; private set; } = String.Empty;
@@ -59,15 +60,15 @@ public bool GatherNDKInfo (Context context)
 				string rev = parts [1].Trim ();
 				NDKRevision = rev;
 
-				Version ver;
-				if (!Version.TryParse (rev, out ver)) {
+				if (!Utilities.ParseAndroidPkgRevision (rev, out Version? ver, out string tag)) {
 					Log.ErrorLine ($"Unable to parse NDK revision '{rev}' as a valid version string");
 					return false;
 				}
 
 				NDKVersionMajor = ver.Major.ToString ();
 				NDKVersionMinor = ver.Minor.ToString ();
 				NDKVersionMicro = ver.Build.ToString ();
+				NDKVersionTag = tag;
 				break;
 			}
 

build-tools/xaprepare/xaprepare/Application/MonoJitRuntime.cs

@@ -24,7 +24,7 @@ public override void Init (Context context)
 			OutputMonoBtlsFilename        = Configurables.Defaults.MonoRuntimeOutputMonoBtlsFilename;
 			OutputMonoPosixHelperFilename = Configurables.Defaults.MonoRuntimeOutputMonoPosixHelperFilename;
 			OutputProfilerFilename        = Configurables.Defaults.MonoRuntimeOutputProfilerFilename;
-			Strip                         = Path.Combine (Configurables.Paths.AndroidToolchainBinDirectory, $"{Configurables.Defaults.AndroidToolchainPrefixes [Name]}-strip");
+			Strip                         = Path.Combine (Configurables.Paths.AndroidToolchainBinDirectory, "llvm-strip");
 		}
 	}
 }

build-tools/xaprepare/xaprepare/Application/Utilities.cs

@@ -29,6 +29,29 @@ static partial class Utilities
 
 		public static readonly Encoding UTF8NoBOM = new UTF8Encoding (false);
 
+		public static bool ParseAndroidPkgRevision (string? v, out Version? version, out string? tag)
+		{
+			string? ver = v?.Trim ();
+			version = null;
+			tag = null;
+			if (String.IsNullOrEmpty (ver))
+				return false;
+
+			if (ver!.IndexOf ('.') < 0)
+				ver = $"{ver}.0";
+
+			int tagIdx = ver.IndexOf ('-');
+			if (tagIdx >= 0) {
+				tag = ver.Substring (tagIdx + 1);
+				ver = ver.Substring (0, tagIdx - 1);
+			}
+
+			if (Version.TryParse (ver, out version))
+				return true;
+
+			return false;
+		}
+
 		public static bool AbiChoiceChanged (Context context)
 		{
 			string cacheFile = Configurables.Paths.MonoRuntimesEnabledAbisCachePath;

build-tools/xaprepare/xaprepare/ConfigAndData/BuildAndroidPlatforms.cs

@@ -5,8 +5,8 @@ namespace Xamarin.Android.Prepare
 {
 	class BuildAndroidPlatforms
 	{
-		public const string AndroidNdkVersion = "22b";
-		public const string AndroidNdkPkgRevision = "22.1.7171670";
+		public const string AndroidNdkVersion = "23";
+		public const string AndroidNdkPkgRevision = "23.0.7599858";
 
 		public static readonly List<AndroidPlatform> AllPlatforms = new List<AndroidPlatform> {
 			new AndroidPlatform (apiName: "",                       apiLevel: 1,  platformID: "1"),

build-tools/xaprepare/xaprepare/ConfigAndData/Configurables.cs

@@ -398,8 +398,8 @@ public static partial class Paths
 			public static string AndroidToolchainRootDirectory       => GetCachedPath (ref androidToolchainRootDirectory,       () => Path.Combine (AndroidNdkDirectory, "toolchains", "llvm", "prebuilt", NdkToolchainOSTag));
 			public static string AndroidToolchainBinDirectory        => GetCachedPath (ref androidToolchainBinDirectory,        () => Path.Combine (AndroidToolchainRootDirectory, "bin"));
 			public static string AndroidToolchainSysrootLibDirectory => GetCachedPath (ref androidToolchainSysrootLibDirectory, () => Path.Combine (AndroidToolchainRootDirectory, "sysroot", "usr", "lib"));
-			public static string WindowsBinutilsInstallDir           => GetCachedPath (ref windowsBinutilsInstallDir,           () => Path.Combine (InstallMSBuildDir, "ndk"));
-			public static string HostBinutilsInstallDir              => GetCachedPath (ref hostBinutilsInstallDir,              () => Path.Combine (InstallMSBuildDir, ctx.Properties.GetRequiredValue (KnownProperties.HostOS), "ndk"));
+			public static string WindowsBinutilsInstallDir           => GetCachedPath (ref windowsBinutilsInstallDir,           () => Path.Combine (InstallMSBuildDir, "binutils"));
+			public static string HostBinutilsInstallDir              => GetCachedPath (ref hostBinutilsInstallDir,              () => Path.Combine (InstallMSBuildDir, ctx.Properties.GetRequiredValue (KnownProperties.HostOS), "binutils"));
 			public static string BinutilsCacheDir                    => ctx.Properties.GetRequiredValue (KnownProperties.AndroidToolchainCacheDirectory);
 			public static string AndroidBuildToolsCacheDir           => ctx.Properties.GetRequiredValue (KnownProperties.AndroidToolchainCacheDirectory);
 

build-tools/xaprepare/xaprepare/ConfigAndData/Dependencies/AndroidToolchain.cs

@@ -69,7 +69,7 @@ public AndroidToolchain ()
 				new AndroidToolchainComponent ("docs-24_r01",                                       destDir: "docs", pkgRevision: "1", dependencyType: AndroidToolchainComponentType.BuildDependency),
 				new AndroidToolchainComponent ("android_m2repository_r47",                          destDir: Path.Combine ("extras", "android", "m2repository"), pkgRevision: "47.0.0", dependencyType: AndroidToolchainComponentType.BuildDependency),
 				new AndroidToolchainComponent ($"x86_64-29_r07-{osTag}",                            destDir: Path.Combine ("system-images", "android-29", "default", "x86_64"), relativeUrl: new Uri ("sys-img/android/", UriKind.Relative), pkgRevision: "7", dependencyType: AndroidToolchainComponentType.EmulatorDependency),
-				new AndroidToolchainComponent ($"android-ndk-r{AndroidNdkVersion}-{osTag}-x86_64",  destDir: AndroidNdkDirectory, pkgRevision: AndroidPkgRevision),
+				new AndroidToolchainComponent ($"android-ndk-r{AndroidNdkVersion}-{osTag}",         destDir: AndroidNdkDirectory, pkgRevision: AndroidPkgRevision),
 				new AndroidToolchainComponent ($"{XABuildToolsPackagePrefix}build-tools_r{XABuildToolsVersion}-{altOsTag}",    destDir: Path.Combine ("build-tools", XABuildToolsFolder), isMultiVersion: true),
 				new AndroidToolchainComponent ($"commandlinetools-{cltOsTag}-{CommandLineToolsVersion}",
 					destDir: Path.Combine ("cmdline-tools", CommandLineToolsFolder), isMultiVersion: true),

build-tools/xaprepare/xaprepare/Steps/Step_Android_SDK_NDK.cs

@@ -307,37 +307,21 @@ bool IsInstalled (AndroidToolchainComponent component, string path, out bool mis
 				return false;
 			}
 
-			if (!ParseVersion (pkgRevision, out Version? pkgVer) || pkgVer == null) {
+			if (!Utilities.ParseAndroidPkgRevision (pkgRevision, out Version? pkgVer, out string pkgTag) || pkgVer == null) {
 				Log.DebugLine ($"Failed to parse a valid version from Pkg.Revision ({pkgRevision}) for component '{component.Name}'. Component will be reinstalled.");
 				return false;
 			}
 
-			if (!ParseVersion (component.PkgRevision, out Version? expectedPkgVer) || expectedPkgVer == null)
+			if (!Utilities.ParseAndroidPkgRevision (component.PkgRevision, out Version? expectedPkgVer, out string expectedTag) || expectedPkgVer == null)
 				throw new InvalidOperationException ($"Invalid expected package version for component '{component.Name}': {component.PkgRevision}");
 
-			bool equal = pkgVer == expectedPkgVer;
+			bool equal = (pkgVer == expectedPkgVer) && (pkgTag == expectedTag);
 			if (!equal)
-				Log.DebugLine ($"Installed version of '{component.Name}' ({pkgVer}) is different than the required one ({expectedPkgVer})");
+				Log.DebugLine ($"Installed version of '{component.Name}' ({pkgRevision}) is different than the required one ({component.PkgRevision})");
 
 			return equal;
 		}
 
-		bool ParseVersion (string? v, out Version? version)
-		{
-			string? ver = v?.Trim ();
-			version = null;
-			if (String.IsNullOrEmpty (ver))
-				return false;
-
-			if (ver!.IndexOf ('.') < 0)
-				ver = $"{ver}.0";
-
-			if (Version.TryParse (ver, out version))
-				return true;
-
-			return false;
-		}
-
 		bool IsNdk (AndroidToolchainComponent component)
 		{
 			return component.Name.StartsWith ("android-ndk", StringComparison.OrdinalIgnoreCase);

src/Xamarin.Android.Build.Tasks/Tasks/GetAotArguments.cs

@@ -312,14 +312,20 @@ string GetLdFlags(NdkTools ndk, AndroidTargetArch arch, int level, string toolPr
 				}
 
 				string toolchainLibDir;
-				if (ndk.UsesClang)
-					toolchainLibDir = GetNdkToolchainLibraryDir (ndk, toolchainPath, arch);
-				else
+				if (ndk.UsesClang) {
+					if (ndk.NoBinutils) {
+						toolchainLibDir = String.Empty;
+					} else {
+						toolchainLibDir = GetNdkToolchainLibraryDir (ndk, toolchainPath, arch);
+					}
+				} else
 					toolchainLibDir = GetNdkToolchainLibraryDir (ndk, toolchainPath);
 
 				var libs = new List<string> ();
 				if (ndk.UsesClang) {
-					libs.Add ($"-L{toolchainLibDir.TrimEnd ('\\')}");
+					if (!String.IsNullOrEmpty (toolchainLibDir)) {
+						libs.Add ($"-L{toolchainLibDir.TrimEnd ('\\')}");
+					}
 					libs.Add ($"-L{androidLibPath.TrimEnd ('\\')}");
 
 					if (arch == AndroidTargetArch.Arm) {
@@ -329,7 +335,9 @@ string GetLdFlags(NdkTools ndk, AndroidTargetArch arch, int level, string toolPr
 					}
 				}
 
-				libs.Add (Path.Combine (toolchainLibDir, "libgcc.a"));
+				if (!String.IsNullOrEmpty (toolchainLibDir)) {
+					libs.Add (Path.Combine (toolchainLibDir, "libgcc.a"));
+				}
 				libs.Add (Path.Combine (androidLibPath, "libc.so"));
 				libs.Add (Path.Combine (androidLibPath, "libm.so"));
 

src/Xamarin.Android.Build.Tasks/Tasks/ResolveSdksTask.cs

@@ -1,23 +1,23 @@
-// 
+//
 // ResolveSdksTask.cs
-//  
+//
 // Author:
 //       Michael Hutchinson <mhutchinson@novell.com>
 //       Jonathan Pryor <jonp@xamarin.com>
-// 
+//
 // Copyright (c) 2010 Novell, Inc.
 // Copyright (c) 2013 Xamarin Inc.
-// 
+//
 // Permission is hereby granted, free of charge, to any person obtaining a copy
 // of this software and associated documentation files (the "Software"), to deal
 // in the Software without restriction, including without limitation the rights
 // to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
 // copies of the Software, and to permit persons to whom the Software is
 // furnished to do so, subject to the following conditions:
-// 
+//
 // The above copyright notice and this permission notice shall be included in
 // all copies or substantial portions of the Software.
-// 
+//
 // THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 // IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 // FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
@@ -85,7 +85,7 @@ public override bool RunTask ()
 			}
 			MonoAndroidBinPath  = MonoAndroidHelper.GetOSBinPath () + Path.DirectorySeparatorChar;
 			MonoAndroidLibPath  = MonoAndroidHelper.GetOSLibPath () + Path.DirectorySeparatorChar;
-			AndroidBinUtilsPath = MonoAndroidBinPath + "ndk" + Path.DirectorySeparatorChar;
+			AndroidBinUtilsPath = MonoAndroidBinPath + "binutils" + Path.DirectorySeparatorChar;
 
 			var minVersion      = Version.Parse (MinimumSupportedJavaVersion);
 			var maxVersion      = Version.Parse (LatestSupportedJavaVersion);
@@ -139,4 +139,3 @@ public override bool RunTask ()
 		}
 	}
 }
-

src/Xamarin.Android.Build.Tasks/Tests/Xamarin.Android.Build.Tests/Tasks/NdkUtilTests.cs

@@ -34,6 +34,7 @@ public void TestNdkUtil ()
 				var ndkDir = AndroidNdkPath;
 				var sdkDir = AndroidSdkPath;
 				NdkTools ndk = NdkTools.Create (ndkDir, log);
+				ndk.OSBinPath = SetUp.OSBinDirectory;
 				MonoAndroidHelper.AndroidSdk = new AndroidSdkInfo ((arg1, arg2) => { }, sdkDir, ndkDir, AndroidSdkResolver.GetJavaSdkPath ());
 				var platforms = ndk.GetSupportedPlatforms ();
 				Assert.AreNotEqual (0, platforms.Count (), "No platforms found");

src/Xamarin.Android.Build.Tasks/Tests/Xamarin.Android.Build.Tests/Utilities/BaseTest.cs

@@ -42,6 +42,11 @@ public class SetUp {
 				private set;
 			}
 
+			public static string OSBinDirectory {
+				get;
+				private set;
+			}
+
 			static SetUp ()
 			{
 #if NETCOREAPP
@@ -54,6 +59,16 @@ static SetUp ()
 					CommercialBuildAvailable = File.Exists (Path.Combine (builder.AndroidMSBuildDirectory, "Xamarin.Android.Common.Debugging.targets"));
 					AndroidMSBuildDirectory = builder.AndroidMSBuildDirectory;
 				}
+
+				string osSubdirName;
+				if (TestEnvironment.IsLinux) {
+					osSubdirName = "Linux";
+				} else if (TestEnvironment.IsMacOS) {
+					osSubdirName = "Darwin";
+				} else {
+					osSubdirName = String.Empty;
+				}
+				OSBinDirectory = Path.Combine (AndroidMSBuildDirectory, osSubdirName);
 			}
 
 			[OneTimeSetUp]