QTlsBackendOpenSSL: Use a function-static variable in ensureLibraryLoaded()

Replace a combination of a mutex and a state variable by
a function-local variable initialized by lambda.

C++17 standard guarantees that the lambda is called only once and
that any other callers will waiting for initialization to complete.

The mutex that was replaced is also used in ensureCiphersAndCertsLoaded()
but that seems to be a false sharing.

Task-number: QTBUG-103559
Change-Id: Idb269a24b53cf3812ca9630ab4fc87f99ab16d55
Reviewed-by: Timur Pocheptsov <timur.pocheptsov@qt.io>
Reviewed-by: Mårten Nordheim <marten.nordheim@qt.io>
Reviewed-by: Qt CI Bot <qt_ci_bot@qt-project.org>

0 files changed, 0 insertions, 0 deletions