Unity 2020 Android build fails with Code stripping, even empty one. Failed to link 'libunity.so'

Or course I could switch off code stripping (internet answer) but then my build goes from 23Mb to 28Mb. A tad annoying considering how long it took to get it down to 23Mb. I'm assuming it's an installation problem because an empty project build with stripping also fails with the same error. Maybe NDK related but out of my depth.

Anyway the error message in build:

Code (CSharp):

1. C:/Program Files (x86)/Microsoft Visual Studio/2019/Community/Common7/IDE/2020.3.25f1/Editor/Data/PlaybackEngines/AndroidPlayer/NDK/toolchains/llvm/prebuilt/windows-x86_64/bin/../lib/gcc/arm-linux-androideabi/4.9.x/../../../../arm-linux-androideabi/bin\ld.gold.exe: error: cannot find -latomic
2. clang++.exe: error: linker command failed with exit code 1 (use -v to see invocation)

Code (CSharp):

1. CommandInvokationFailure: Failed to link 'libunity.so'.
2. C:/Program Files (x86)/Microsoft Visual Studio/2019/Community/Common7/IDE/2020.3.25f1/Editor/Data/PlaybackEngines/AndroidPlayer/NDK/toolchains/llvm/prebuilt/windows-x86_64/bin/clang++.exe @"Temp/StagingArea/strip/armeabi-v7a/libunity.rsp"
3.  
4. stderr[
5. C:/Program Files (x86)/Microsoft Visual Studio/2019/Community/Common7/IDE/2020.3.25f1/Editor/Data/PlaybackEngines/AndroidPlayer/NDK/toolchains/llvm/prebuilt/windows-x86_64/bin/../lib/gcc/arm-linux-androideabi/4.9.x/../../../../arm-linux-androideabi/bin\ld.gold.exe: error: cannot find -latomic
6. clang++.exe: error: linker command failed with exit code 1 (use -v to see invocation)
7. ]
8. stdout[
9.  
10. ]
11. exit code: 1
12. UnityEditor.Android.Command.WaitForProgramToRun (UnityEditor.Utils.Program p, UnityEditor.Android.Command+WaitingForProcessToExit waitingForProcessToExit, System.String errorMsg) (at <fc7be335e11c4872b360501993848bfb>:0)
13. UnityEditor.Android.Command.Run (System.Diagnostics.ProcessStartInfo psi, UnityEditor.Android.Command+WaitingForProcessToExit waitingForProcessToExit, System.String errorMsg) (at <fc7be335e11c4872b360501993848bfb>:0)
14. UnityEditor.Android.Command.Run (System.String command, System.String args, System.String workingdir, System.String errorMsg) (at <fc7be335e11c4872b360501993848bfb>:0)
15. UnityEditor.Android.PostProcessor.Tasks.BuildSharedLibrary.Link (UnityEditor.Android.PostProcessor.PostProcessorContext context, UnityEditor.Android.AndroidNDKTools ndk, UnityEditor.Android.AndroidTargetDeviceType deviceType, System.Collections.Generic.IEnumerable`1[T] objects) (at <fc7be335e11c4872b360501993848bfb>:0)
16. UnityEditor.Android.PostProcessor.Tasks.BuildSharedLibrary.Build (UnityEditor.Android.PostProcessor.PostProcessorContext context, UnityEditor.Android.AndroidNDKTools ndk, UnityEditor.Android.AndroidTargetDeviceType deviceType) (at <fc7be335e11c4872b360501993848bfb>:0)
17. UnityEditor.Android.PostProcessor.Tasks.BuildSharedLibrary.Execute (UnityEditor.Android.PostProcessor.PostProcessorContext context) (at <fc7be335e11c4872b360501993848bfb>:0)
18. UnityEditor.Android.PostProcessor.PostProcessRunner.RunAllTasks (UnityEditor.Android.PostProcessor.PostProcessorContext context) (at <fc7be335e11c4872b360501993848bfb>:0)
19. Rethrow as BuildFailedException: Exception of type 'UnityEditor.Build.BuildFailedException' was thrown.
20. UnityEditor.Android.PostProcessor.CancelPostProcess.AbortBuild (System.String title, System.String message, System.Exception ex) (at <fc7be335e11c4872b360501993848bfb>:0)
21. UnityEditor.Android.PostProcessor.PostProcessRunner.RunAllTasks (UnityEditor.Android.PostProcessor.PostProcessorContext context) (at <fc7be335e11c4872b360501993848bfb>:0)
22. UnityEditor.Android.PostProcessAndroidPlayer.PostProcess (UnityEditor.BuildTarget target, System.String stagingAreaData, System.String stagingArea, System.String playerPackage, System.String installPath, System.String companyName, System.String productName, UnityEditor.BuildOptions options, UnityEditor.RuntimeClassRegistry usedClassRegistry, UnityEditor.Build.Reporting.BuildReport report) (at <fc7be335e11c4872b360501993848bfb>:0)
23. UnityEditor.Android.AndroidBuildPostprocessor.PostProcess (UnityEditor.Modules.BuildPostProcessArgs args, UnityEditor.BuildProperties& outProperties) (at <fc7be335e11c4872b360501993848bfb>:0)
24. UnityEditor.PostprocessBuildPlayer.Postprocess (UnityEditor.BuildTargetGroup targetGroup, UnityEditor.BuildTarget target, System.String installPath, System.String companyName, System.String productName, System.Int32 width, System.Int32 height, UnityEditor.BuildOptions options, UnityEditor.RuntimeClassRegistry usedClassRegistry, UnityEditor.Build.Reporting.BuildReport report) (at <7ac35247888b44f4a7e290f1f6bb33f3>:0)
25. UnityEditor.BuildPipeline:BuildPlayer(String[], String, BuildTarget, BuildOptions)
26. TMAppProjectList:PerformPlatformBuild(BuildTargetGroup, BuildTarget, String[], String, BuildOptions) (at Assets/Editor/TMAppProjectList.cs:855)
27. TMAppProjectList:BuildCurrent() (at Assets/Editor/TMAppProjectList.cs:690)

 

"Honey, I shrunk the bundle!". Thank you so much for your suggestion. It looks like that is exactly what the problem was. And my last problem left on my next release so very happy.
It appears in 2019 when I upgraded from unity 2017 to 2018 that unity was first installed to the VS directory. No problems then, but at Christmas when I upgraded to Unity 2019 and then 2020, they used the same installation directory and the stripping stopped working.