EntryPointNotFoundException when Window.ShowDialog() called on Windows 1511

[SKasperczyk]

Describe the bug

When trying to show window in dialog mode via Window.ShowDialog() on Windows 1511 the following exception is thrown and application crashes:
System.EntryPointNotFoundException
Unable to find an entry point named 'AdjustWindowRectExForDpi' in DLL 'user32.dll'.

To Reproduce

Execute Window.ShowDialog() on Windows 1511.

Expected behavior

Apparently AdjustWindowRectEx() should be called instead of AdjustWindowRectExForDpi() at WindowImpl.cs: RECT WindowImpl.ClientRectToWindowRect(RECT clientRect, WindowStyles? styleOverride, WindowStyles? extendedStyleOverride) for windows 1511 or earlier.

Avalonia version

11.1.0-beta1

OS

Windows

Additional context

I might be wrong, but it seems that Windows10_1607 const in PlatformConstants.cs is defined wrong.
Shouldn't it be 10.0.14393 instead of 10.0.1607. Crashed system was reported as 10.0.10586 so it might be that 10.0.10568 > 10.0.1607. Though I'm no cerain about that as I'm unable to check what Win32Platform.WindowsVersion is actually returning.

Either way, it looks like following statement:

var result = Win32Platform.WindowsVersion < PlatformConstants.Windows10_1607
                ? AdjustWindowRectEx(ref clientRect, (uint)style, false, (uint)extendedStyle)
                : AdjustWindowRectExForDpi(ref clientRect, style, false, extendedStyle, (uint)(RenderScaling * StandardDpi));

calls always AdjustWindowRectExForDpi()

[maxkatz6]

I might be wrong, but it seems that Windows10_1607 const in PlatformConstants.cs is defined wrong.

That's correct. It should be 10.0.14393.

[timunie]

@SKasperczyk a PR is welcome 🤗