Document the lchflags(2) syscall.

lib/libc/sys/Makefile.inc

@@ -90,7 +90,7 @@ MAN+=	sched_get_priority_max.2 sched_setparam.2 \
 MLINKS+=access.2 eaccess.2
 MLINKS+=brk.2 sbrk.2
 MLINKS+=chdir.2 fchdir.2
-MLINKS+=chflags.2 fchflags.2
+MLINKS+=chflags.2 fchflags.2 chflags.2 lchflags.2
 MLINKS+=chmod.2 fchmod.2 chmod.2 lchmod.2
 MLINKS+=chown.2 fchown.2 chown.2 lchown.2
 MLINKS+=clock_gettime.2 clock_getres.2 clock_gettime.2 clock_settime.2

lib/libc/sys/chflags.2

@@ -37,6 +37,7 @@
 .Os
 .Sh NAME
 .Nm chflags ,
+.Nm lchflags ,
 .Nm fchflags
 .Nd set file flags
 .Sh LIBRARY
@@ -47,6 +48,8 @@
 .Ft int
 .Fn chflags "const char *path"  "u_long flags"
 .Ft int
+.Fn lchflags "const char *path" "int flags"
+.Ft int
 .Fn fchflags "int fd" "u_long flags"
 .Sh DESCRIPTION
 The file whose name
@@ -57,6 +60,16 @@ or referenced by the descriptor
 has its flags changed to
 .Fa flags .
 .Pp
+The
+.Fn lchflags
+system call is like
+.Fn chflags
+except in the case where the named file is a symbolic link,
+in which case
+.Fn lchflags
+will change the flags of the link itself,
+rather than the file it points to.
+.Pp
 The flags specified are formed by
 .Em or Ns 'ing
 the following values