configure: Add -fno-builtin-strftime flag with gcc to avoid warning.
configure: Add -fno-builtin-strftime flag with gcc to avoid warning.

LTD-Beget/dovecot,LTD-Beget/dovecot,LTD-Beget/dovecot,LTD-Beget/dovecot,LTD-Beget/dovecot