Support ARM64 on Windows Desktop

[JunielKatarn]

Summary

Produce native ARM64 binaries for Windows Desktop (Windows 8.1 and later).

Work will be tracked on this fork branch:
https://github.com/jurocha-ms/react-native-windows/tree/desktop-arm64

Motivation

Partner project (MS Office) now requires ARM64 builds of React Native. This requires porting react-native-win32.dll.

Dependencies

To deliver this new platform build, we need to either port or stub the following external libraries:

• ReactWindows.OpenSSL.StdCall.Static
  Available in version 1.0.2-p.5.
• ReactNative.V8Jsi.Windows
  Currently non-critical because we default to ChakraCore. Follow up with @tudorms.
• Microsoft.googletest.v140.windesktop.msvcstl.static.rt-dyn
  Optional. Skipping. Only needed for test projects. Some of those are only supported on x64 (not even x86).
• ChakraCore.Debugger
  Awaiting PR Add ARM64 support ChakraCore-Debugger#92
  • Microsoft.ChakraCore.vc140
    Package ReactWindows.ChakraCore.ARM64 released.

[Poopooracoocoo]

Why do you guys use ChakraCore? And do you guys know if Facebook will be using RNW for Instagram? That'd convince a lot of people. And how come Skype moved away from RNW? What does that say to anyone thinking of using RNW?

[asklar]

@Poopooracoocoo Skype never used RNW, they had a thing called ReactXP: https://microsoft.github.io/reactxp/blog/2017/04/27/building-skype-on-reactxp.html

My personal opinion (not Microsoft-official :-) ) is that the cost of updating and maintaining ReactXP to keep up with react native became too much. At the end of the day they are an app/service team, not an app framework team.

[Poopooracoocoo]

@asklar thank you for the response. <3 I didn't want a microsoft official response anyway :p
let's hope they switch to RNW and that Facebook notices and uses your project. :)

I thought that Microsoft wasn't using ChakraCore: chakra-core/ChakraCore#6384

[JunielKatarn]

Reopening, this issue was not meant to be fully closed by #5864.

We need to set the V8 (and Hermes?) story straight so we have no pending relevant dependencies.
See the checklist in the description.

[NickGerleman]

I believe this was completed. Please reopen if this wasn't.

[JunielKatarn]

I believe this was completed. Please reopen if this wasn't.

See the Dependencies section in the description.

Those correspond to other projects. I leave it to your criteria if those should be considered into keeping a RNW issue open or not.