Ondřej Surý authored Dec 02, 2019 and Ondřej Surý committed Dec 03, 2019

Previously, the dns_name API used isc_thread_key API for TLS, which is
fairly complicated and requires initialization of memory contexts, etc.
This part of code was refactored to use a ISC_THREAD_LOCAL pointer which
greatly simplifies the whole code related to storing TLS variables.