* When determining if a shared_ptr already exists, use a test on the weak_ptr instead of a try/catch block.
* When determining if a shared_ptr already exists, use a test on the weak_ptr instead of a try/catch block.
* weak_from_this is only available in C++17 and later
* Switch to use feature flag instead of C++ version flag.
* Add Microsoft-specific check.
* Avoid undefined preprocessor macro warning treated as error.
* Simplify shared_from_this in init_holder
* Include <version> in detail/common.h (~stolen~ borrowed from @bstaletic's #2816)
* Move class_::get_shared_from_this to detail::try_get_shared_from_this
* Simplify try_get_shared_from_this by using weak_ptr::lock()
Co-authored-by: Yannick Jadoul <yannick.jadoul@belgacom.net>
