K 10
svn:author
V 6
kevans
K 8
svn:date
V 27
2019-12-12T01:41:55.676701Z
K 7
svn:log
V 449
Add sigsetop extensions commonly found in musl libc and glibc

These functions (sigandset, sigisemptyset, sigorset) are commonly available
in at least musl libc and glibc; sigorset, at least, has proven quite useful
in qemu-bsd-user work for tracking the current process signal mask in a more
self-documenting/aesthetically pleasing manner.

Reviewed by:	bapt, jilles, pfg
MFC after:	1 week
Differential Revision:	https://reviews.freebsd.org/D22187

END