--- /dev/null
+--- dirname.3 2004-11-25 11:38:00.000000000 -0800
++++ dirname.3.edit 2006-07-12 11:18:01.000000000 -0700
+@@ -36,7 +36,9 @@
+ .Sh SYNOPSIS
+ .In libgen.h
+ .Ft char *
+-.Fn dirname "const char *path"
++.Fo dirname
++.Fa "char *path"
++.Fc
+ .Sh DESCRIPTION
+ The
+ .Fn dirname
+@@ -88,12 +90,25 @@
+ .Fn dirname
+ may modify the contents of the string passed to
+ .Fn dirname ;
+-this should be taken into account when writing code which calls this function
+-if portability is desired.
++if portability is desired,
++this should be taken into account when writing code which calls this function.
++.Sh LEGACY SYNOPSIS
++.Fd #include <libgen.h>
++.Pp
++.Ft char *
++.br
++.Fo dirname
++.Fa "const char *path"
++.Fc ;
++.Pp
++In legacy mode,
++.Fa path
++will not be changed.
+ .Sh SEE ALSO
+ .Xr basename 1 ,
+ .Xr dirname 1 ,
+-.Xr basename 3
++.Xr basename 3 ,
++.Xr compat 5
+ .Sh STANDARDS
+ The
+ .Fn dirname