add ARM64 windows support

[jmklix]

Describe the feature

Initial request from aws-sdk-cpp

Use Case

So the aws-sdk-cpp can be build on ARM64 windows platforms

Proposed Solution

This involves adding support for atomics on ATM64 windows builds. Current exception seen here:

#if !(defined(_M_IX86) || defined(_M_X64))
#    error Atomics are not currently supported for non-x86 MSVC platforms

Other Information

No response

Acknowledgements

• I may be able to implement this feature request
• This feature might incur a breaking change

[blaymanGM]

I would like to add that this support would be helpful for our team. Reason we need ARM64 support is for Hololens 2 devices (ARM64 Windows Architecture)