libstdc++: Replace implicit lambda capture of 'this' [PR116964]
C++20 deprecates implicit capture of 'this', so change [=] to [this] for
all lambda expressions in <shared_mutex>. This only shows up on targets
where _GLIBCXX_USE_PTHREAD_RWLOCK_T is not defined, as we have an
alternative implementation of shared mutexes in that case.
libstdc++-v3/ChangeLog:
PR libstdc++/116964
* include/std/shared_mutex (__shared_mutex_cv): Use [this] for
lambda captures.
(shared_timed_mutex) [!_GLIBCXX_USE_PTHREAD_RWLOCK_T]: Likewise.