- Update the manual page to show that the associated header file

is <strings.h> and not <string.h> anymore.
 - Tell the reader about this change in the HISTORY section.
 - Switch to use an ANSI-C function definition.
 - Include <strings.h> instead of <string.h> in the source file.

lib/libc/string/ffs.3

@@ -43,7 +43,7 @@
 .Sh LIBRARY
 .Lb libc
 .Sh SYNOPSIS
-.In string.h
+.In strings.h
 .Ft int
 .Fn ffs "int value"
 .Sh DESCRIPTION
@@ -62,3 +62,10 @@ The
 .Fn ffs
 function appeared in
 .Bx 4.3 .
+Its prototype existed previously in
+.Aq Pa string.h
+before it was moved to
+.Aq Pa strings.h
+for
+.St -p1003.1-2001
+compliance.

lib/libc/string/ffs.c

@@ -37,14 +37,13 @@ static char sccsid[] = "@(#)ffs.c	8.1 (Berkeley) 6/4/93";
 #include <sys/cdefs.h>
 __FBSDID("$FreeBSD$");
 
-#include <string.h>
+#include <strings.h>
 
 /*
  * ffs -- vax ffs instruction
  */
 int
-ffs(mask)
-	int mask;
+ffs(int mask)
 {
 	int bit;