Improve nvda helper by compiling with C++20 and disabling the /permissive flag

[LeonarddeR]

Link to issue number:

None

Summary of the issue:

NVDAHelper was compiled with C++17, it could be compiled with C++20

1. Visual Studio has support for C++20.
2. WinRT is C++20 (Convert NVDAHelper LocalWin10 to C++/WinRT #11768).
3. Compiling with C++20 ensures we're more conformant.
   • Passing string literals to parameters expecting wchar_t* or BSTR is no longer supported. This ensures safe code. See here for a rationale.
   • The/permissive- flag (note the minus symbol disabling permissive mode), ensuring conformance in more areas. See here

Description of how this pull request fixes the issue:

• Change build params so nvdaHelper is built with C++20 and disable permissive mode.
• Fix errors (wchar_t* or BSTR from string literal)

Testing strategy:

The following areas of code have been touched and need testing:

• UIA custom automation types (comments in Excel with UIA and Windows 11)
• Adobe reader virtual buffers
• Gecko virtual buffers
• MSHTML virtual buffers
• Webkit virtual buffers

Other changes are mainly changes from char* to const char*, so unlikely to cause any harm.

I did some quick tests and didn't find anything crucial, probably best to test this in Alpha.

Known issues with pull request:

None

Change log entries:

For Developers

• NVDAHelper is now C++20 and built with the /permissive- compiler flag, which ensures better conformance to C++ standards.

Code Review Checklist:

• Pull Request description:
  • description is up to date
  • change log entries
• Testing:
  • Unit tests
  • System (end to end) tests
  • Manual testing
• API is compatible with existing add-ons.
• Documentation:
  • User Documentation
  • Developer / Technical Documentation
  • Context sensitive help for GUI changes
• UX of all users considered:
  • Speech
  • Braille
  • Low Vision
  • Different web browsers
  • Localization in other languages / culture than English

[LeonarddeR]

The build issue should have been fixed. It was due to a bad merge.

[feerrenrut]

Unless there is some urgency on this that I'm not aware of, I think it would be better to merge this in the new dev cycle. Applying 2022.2 milestone.

[seanbudd]

We plan to merge this soon for 2022.2, and are ready to revert if there are issues

[LeonarddeR]

It looks like the UIA remote library doesn't like C++20 that much. I need to dive into this some more.

[LeonarddeR]

This is now ready for review. Probably want to merge this early.