Application executable is not marked as Windows 10 compatible in the default manifest

[jkotas]

The manifest of self-contained apps does not contain Windows 10 supportedOS element. It means that self-contained applications run with compatibility shims by default.

The proposal based on the offline discussion:

• Stop embedding the manifest in Roslyn for .NET 5 by passing the right command line option to the C# compiler (-nowin32manifest). There is a MS build property that drives this that we should set by default for .NET 5+, unless the app has explicitly provided manifest.
  • This is going to make apps on Linux a bit smaller. The Windows manifest in app.dll is a dead weight on Linux.
• Attach Win10 compatible manifest to apphost by default if there is not one in app.dll.

Related:

• Change Environment.OSVersion to use RtlGetVersion runtime#33651
• Add os supported versions to host core-setup#4700
• Host should add supportedOs to application manifest to avoid shims from the Windows OS - Windows only runtime#3028

[agocke]

@mateoatr Could you take a look at this?

[agocke]

Moving to SDK since the work should be here, and moving to .NET 6 since we won't get to this in the 5.0 time frame.

[agocke]

Moving this to backlog for the moment, but I'd be interested in taking this for 6.0.2xx -- it just requires some coordination with Roslyn.