3.7.7
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Merge branch 'wip/dueno/typo-fixes' into 'master'
keys-win: free certificate context in gnutls_system_key_iter_deinit
ktls: _gnutls_ktls_enable: fix GNUTLS_KTLS_SEND calculation
ktls: sendfile
sockets: fixed compiler warning on Windows x32
locks: replace custom mutex wrappers with "glthread/lock.h"