Create stdbool flag

[LEOYoon-Tsaw]

Pull request

Issue tracker

Fixes will automatically close the related issue

Fixes #

Feature

Use a flag STDBOOL to gate type definition for Bool. The current def to int causes compiler confusion in interoperation with Swift.
Ideally, Bool should use standard C bool instead of int. The use of a flag gate is for compatibility consideration.
Feel free to change the design if this is not the best practice

Unit test

• Done

Manual test

• Done

Code Review

1. Unit and manual test pass
2. GitHub Action CI pass
3. At least one contributor reviews and votes
4. Can be merged clean without conflicts
5. PR will be merged by rebase upstream base

Additional Info

squirrel can be successfully setup to export this flag
LEOYoon-Tsaw/squirrel@39a51fc

[lotem]

Follow-up ideas:

• new APIs use bool;
• rename new APIs so they are never confused with the old APIs that use int for boolean;
• guard the new APIs with a build flag;
• the release build of the library on macOS provides both old and new APIs;
• to use the new APIs, client code includes a separate header file with deferent macro definition for Bool.

[LEOYoon-Tsaw]

Will be addressed by #877