[RFC]: Document patch for F90 derived type support

[Eli Zaretskii]

> Date: Wed, 1 Mar 2006 22:22:29 -0500
> From: Daniel Jacobowitz <drow@false.org>
> Cc: Eli Zaretskii <eliz@gnu.org>, gdb-patches@sources.redhat.com
> 
> My preference is to fix the compiler rather than the debugger here; it
> should output something sensible

Again, the versions of the compiler that are already out there should
not produce wrong types in GDB, IMHO.