We use async-signal-safe (not async-signal safe) elsewhere,
and so does POSIX.
http://pubs.opengroup.org/onlinepubs/9699919799/functions/sigaction.html
Index: sigaction.2
===
RCS file: /cvs/src/lib/libc/sys/sigaction.2,v
retrieving revision 1.61
diff -u -p -r1.61 sigaction.2
--- sigaction.2 31 Aug 2014 01:42:36 - 1.61
+++ sigaction.2 15 Sep 2014 04:30:54 -
@@ -463,7 +463,7 @@ and
.Dv SA_SIGINFO
flags are options commonly found in other operating systems.
The following functions are either reentrant or not interruptible
-by signals and are async-signal safe.
+by signals and are async-signal-safe.
Therefore applications may
invoke them, without restriction, from signal-catching functions:
.Pp