Add HISTORY sections to tree(3), stdarg(3) and sigevent(3)

Submitted by:	gbergling_gmail.com
Approved by:	bcr@(mentor)
MFC after:	1 week
Differential Revision:	https://reviews.freebsd.org/D23832

share/man/man3/sigevent.3

@@ -25,7 +25,7 @@
 .\"
 .\" $FreeBSD$
 .\"
-.Dd July 15, 2016
+.Dd February 25, 2020
 .Dt SIGEVENT 3
 .Os
 .Sh NAME
@@ -119,6 +119,11 @@ notifications must link against the
 .Xr mq_notify 2 ,
 .Xr timer_create 2 ,
 .Xr siginfo 3
+.Sh HISTORY
+The
+.Va sigevent
+structure first appeared in
+.Fx 3.3 .
 .Sh STANDARDS
 The
 .Vt struct sigevent

share/man/man3/stdarg.3

@@ -32,7 +32,7 @@
 .\"	@(#)stdarg.3	8.1 (Berkeley) 6/5/93
 .\" $FreeBSD$
 .\"
-.Dd October 25, 2002
+.Dd February 25, 2020
 .Dt STDARG 3
 .Os
 .Sh NAME
@@ -217,6 +217,18 @@ and
 .Fn va_end
 macros conform to
 .St -isoC-99 .
+.Sh HISTORY
+The
+.Fn va_start ,
+.Fn va_arg
+and
+.Fn va_end
+macros were introduced in
+.St -ansiC .
+The
+.Fn va_copy
+macro was introduced in
+.St -isoC-99 .
 .Sh BUGS
 Unlike the
 .Em varargs

share/man/man3/tree.3

@@ -30,7 +30,7 @@
 .\"
 .\" $FreeBSD$
 .\"
-.Dd September 28, 2019
+.Dd February 25, 2020
 .Dt TREE 3
 .Os
 .Sh NAME
@@ -697,6 +697,9 @@ to indicate an error.
 .Sh SEE ALSO
 .Xr arb 3 ,
 .Xr queue 3
+.Sh HISTORY
+The tree macros first appeared in
+.Fx 4.6 .
 .Sh AUTHORS
 The author of the tree macros is
 .An Niels Provos .