Refer the reader to the correct module for constant definitions.

This closes SF bug #550777.

Doc/lib/libfcntl.tex

@@ -50,7 +50,7 @@ The module defines the following functions:
 \begin{funcdesc}{ioctl}{fd, op, arg}
   This function is identical to the \function{fcntl()} function, except
   that the operations are typically defined in the library module
-  \module{IOCTL}.
+  \refmodule{termios}.
 \end{funcdesc}
 
 \begin{funcdesc}{flock}{fd, op}