Add `--attime` option to tools that perform certificate verification
The tests are currently using the datefudge
program to tweak current time to be used for certificate verification, which replaces time related syscalls with an LD_PRELOAD'ed library. This could be simplified if the tools (certtool, oscptool, gnutls-cli, and gnutls-serv) natively support setting the current time when verifying certificates with a command-line option, as with the -attime
option in OpenSSL s_server and s_client.
Edited by Daiki Ueno