Project has stopped compiling

My project has seemingly stopped compiling for no apparent reason!

Here are the build errors that I am getting:

1>C:\Program Files\Epic Games\UE_4.22\Engine\Source\Runtime\Core\Public\Clang/ClangPlatformMath.h(29): error C3861: '__builtin_clz': identifier not found

1>C:\Program Files\Epic Games\UE_4.22\Engine\Source\Runtime\Core\Public\Clang/ClangPlatformMath.h(46): error C3861: '__builtin_clzll': identifier not found

1>C:\Program Files\Epic Games\UE_4.22\Engine\Source\Runtime\Core\Public\Clang/ClangPlatformMath.h(63): error C3861: '__builtin_ctz': identifier not found

1>C:\Program Files\Epic Games\UE_4.22\Engine\Source\Runtime\Core\Public\Clang/ClangPlatformMath.h(80): error C3861: '__builtin_ctzll': identifier not found

1>C:\Program Files\Epic Games\UE_4.22\Engine\Source\Runtime\Core\Public\Android/AndroidMath.h(10): error C2371: 'FPlatformMath': redefinition; different basic types

1>C:\Program Files\Epic Games\UE_4.22\Engine\Source\Runtime\Core\Public\Windows/WindowsPlatformMath.h(166): note: see declaration of 'FPlatformMath'

no amount of googling these errors, for unreal or otherwise, have provided an answer.

I’ve tried regenerating the project files, and I haven’t changed any build options since it was last successfully compiling as far as I know. Any help would be appreciated, as I’m stumped!

edit: I see that these errors go back to clang files, but I’m not using clang, which is one of the things that confuses me about these errors, or are they being included for another reason?

Problem solved.

Somehow “Android/AndroidMath.h” had been included into one my .cpp files, could have been an auto include gone wrong, or a typing auto-complete error that I didn’t catch.