RTSignal is located in:
runtime/src/AIX386/RTSignal.m3
runtime/src/HPPA/RTSignal.m3
runtime/src/HP300/RTSignal.m3
runtime/src/FreeBSD2/RTSignal.m3
runtime/src/LINUX/RTSignal.m3
runtime/src/LINUXELF/RTSignal.m3
runtime/src/SEQUENT/RTSignal.m3
runtime/src/IRIX5/RTSignal.m3
runtime/src/IBMRT/RTSignal.m3
runtime/src/ALPHA_OSF/RTSignal.m3
runtime/src/SOLgnu/RTSignal.m3
runtime/src/NT386/RTSignal.m3
runtime/src/OKI/RTSignal.m3
runtime/src/NEXT/RTSignal.m3
runtime/src/IBMR2/RTSignal.m3
runtime/src/AP3000/RTSignal.m3
runtime/src/FreeBSD/RTSignal.m3
runtime/src/SUN3/RTSignal.m3
runtime/src/ARM/RTSignal.m3
runtime/src/SUN386/RTSignal.m3
runtime/src/SPARC/RTSignal.m3
runtime/src/DS3100/RTSignal.m3
runtime/src/VAX/RTSignal.m3
runtime/src/SOLsun/RTSignal.m3
runtime/src/UMAX/RTSignal.m3