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.

从 phpsdk-starter.bat 及其 vswhere 调用开始，重点了解在安装了 Visual Studio 2019 和 2022 时如何处理 -s 14.16 请求。确定请求的工具集是否应选择匹配的安装，或者是否应记录该要求。在显式工具集的情况下得到处理，或其安装要求得到明确记录后，即可完成。