For some reason, I wasn't able to get bsd_signal to be exposed by
signal.h, despite using _XOPEN_SOURCE=600 and _GNU_SOURCE/-std=gnu++98.
This hack is close enough. From the man page for bsd_signal(3):
On modern Linux systems, bsd_signal() and signal(2) are equivalent.
But on older systems, signal(2) provided unreliable signal semantics;
see signal(2) for details.
snow flurry
b4596781ea