Fully implemented with the NSS backend only for now.

Reviewed-by: Ray Satiro

Fully implemented with the NSS backend only for now.

Reviewed-by: Ray Satiro

... but make sure we use at least TLSv1.0 according to libcurl API

Reported-by: Cure53
Reviewed-by: Ray Satiro

... in case the handshake completes before entering
CURLM_STATE_PROTOCONNECT

Bug: https://bugzilla.redhat.com/1388162

5 more fixes, 2 more contributors

Serialise the call to PK11_FindSlotByName() to avoid spurious errors in
a multi-threaded environment. The underlying cause is a race condition
in nssSlot_IsTokenPresent().

Bug: https://bugzilla.mozilla.org/1297397

Closes #985

... when we are not asked to use a certificate from file

Some builds of GCC produce output on both stdout and stderr when --help
--verbose is used.  The 2>&1 redirection caused them to be arbitrarily
interleaved with each other because of stream buffering.  Consequently,
grep failed to match the fvisibility= string in the mixed output, even
though the string was present in GCC's standard output.

This led to silently disabling symbol hiding in some builds of curl.