No, Windows. It looks like either broken UnrealBuildTool or VIsual Studio installation. Though, I use VS2017 for more then a year, and now I just updated it.
Using Visual Studio 2017 14.14.26428 toolchain (C:\Program Files (x86)\Microsoft Visual Studio\2017\Community\VC\Tools\MSVC\14.14.26428) and Windows 10.0.16299.0 SDK (C:\Program Files (x86)\Windows Kits\10).
G:\MyDocuments\Unreal Projects\Plugins\Text2LipSync\HostProject\Plugins\Text2LipSync\Source\Text2LipSync\Text2LipSync.Build.cs: warning: Referenced directory 'C:\Program Files\Epic Games\UE_4.20\Engine\Source\Text2LipSync\Public' does not exist.
...]
Using Visual Studio 2017 14.14.26428 toolchain (C:\Program Files (x86)\Microsoft Visual Studio\2017\Community\VC\Tools\MSVC\14.14.26428) and Windows 10.0.16299.0 SDK (C:\Program Files (x86)\Windows Kits\10).
C:\Program Files\Epic Games\UE_4.20\Engine\Source\ThirdParty\Expat\Expat.Build.cs: warning: Referenced directory 'C:\Program Files\Epic Games\UE_4.20\Engine\Source\ThirdParty\Expat\expat-2.2.0\Win64\VS2015\Release' does not exist.
G:\MyDocuments\Unreal Projects\Plugins\Text2LipSync\HostProject\Plugins\Text2LipSync\Source\Text2LipSync\Text2LipSync.Build.cs: warning: Referenced directory 'C:\Program Files\Epic Games\UE_4.20\Engine\Source\Text2LipSync\Public' does not exist.
...]
Running UnrealHeaderTool UE4Game "C:\Program Files\Epic Games\UE_4.20\Engine\Intermediate\Build\Win64\UE4\Development\UE4Game.uhtmanifest" -LogCmds="loginit warning, logexit warning, logdatabase error" -Unattended -WarningsAsErrors -installed
Reflection code generated for UE4Game in 6,7929523 seconds
ERROR: System.IO.DirectoryNotFoundException: Can't find path "G:\MyDocuments\Unreal Projects\Plugins\Text2LipSync\HostProject\Plugins\Text2LipSync\Intermediate\Build\Win64\UE4\Development\Text2LipSync\Text2LipSync.precompiled".
...]
in UnrealBuildTool.PrecompiledManifest.Read(FileReference Location) в C:\Program Files\Epic Games\UE_4.20\Engine\Source\Programs\UnrealBuildTool\System\PrecompiledManifest.cs:line 37