BUILD.rst: document which components of MSVC we install

Since this is what we use on our build machines, it should
be enough.

Closes: #624

Signed-off-by: Frank Lichtenheld <frank@lichtenheld.com>

BUILD.rst

@@ -6,10 +6,27 @@ This is the recommended way of building openvpn-gui on Windows, which is also us
 Prerequisites
 -------------
 
- - Visual Studio 2022 (build tools should be enough)
+ - Visual Studio 2022 (see below for details)
  - CMake
  - vcpkg (add the environment variable ``VCPKG_ROOT`` which points to vcpkg installation)
 
+Visual Studio Components
+------------------------
+
+Having the Build Tools is enough, you do not need the actual IDE.
+In addition to the Microsoft.VisualStudio.Workload.VCTools workload,
+you might also need the following additional components dependending
+on which architectures you build for:
+
+* Microsoft.VisualStudio.Component.VC.ATL.Spectre
+* Microsoft.VisualStudio.Component.VC.ATLMFC.Spectre
+* Microsoft.VisualStudio.Component.UWP.VC.ARM64
+* Microsoft.VisualStudio.Component.VC.Tools.ARM64
+* Microsoft.VisualStudio.Component.VC.ATL.ARM64.Spectre
+* Microsoft.VisualStudio.Component.VC.MFC.ARM64.Spectre
+* Microsoft.VisualStudio.Component.VC.Runtimes.ARM64.Spectre
+* Microsoft.VisualStudio.Component.VC.Runtimes.x86.x64.Spectre
+
 Build steps
 -----------