Multiple Visual Studio installation and explicit toolset selection

If multiple Visual Studio versions are installed, and a toolset is explicitly request (-s option to phpsdk-starter.bat), only the latest Visual Studio is actually tried. E.g. for me I have Visual Studio 2019 and 2022, and have MSVC v141 installed only for Visual Studio 2019. Then doing phpsdk-starter.bat -c vc15 -a x64 -s 14.16 failed,

I think that is fixable by being more specific for vswhere -requires Microsoft.VisualStudio.Component.VC.Tools.x86.x64 (in my case vswhere -requires Microsoft.VisualStudio.Component.VC.v141.x86.x64 would do), but it doesn't seem worth the trouble. Might still be good idea to document, that you either need to have the exact Visual Studio version you want to build with installed, or that you need to install older toolsets for the latest Visual Studio you have installed.

Start with phpsdk-starter.bat and its vswhere invocation, focusing on how the -s 14.16 request is handled when Visual Studio 2019 and 2022 are installed. Determine whether the requested toolset should select the matching installation or whether the requirement should be documented. Done when the explicit-toolset case is handled or its installation requirements are clearly documented.