HelenOS sources

SIGTTOU           157 uspace/lib/posix/include/posix/signal.h 	_TOP_SIGNAL = SIGTTOU
SIGTTOU           123 uspace/lib/posix/src/signal.c 	case SIGTTOU:
SIGTTOU           221 uspace/lib/posix/src/string.c 		[SIGTTOU] = "SIGTTOU (Background process attempting write)",