Symbol: thread_current_on
usr.bin/mail/thread.c
1698
thread_current_on(str, modflags, 1);
usr.bin/mail/thread.c
1727
thread_current_on(str, modflags, 0);
usr.bin/mail/thread.c
1754
thread_current_on(__UNCONST("Message-Id"), 0, 1);