iq2000 trampolines

[DJ Delorie]

The iq2000 is a harvard architecture, so cannot support trampolines in
the usual way.  It tries, but it ends up writing the trampoline to
data memory, then executing the corresponding location in instruction
memory.

What's the preferred way of letting the user know this?  Aside from
the hack (below) which I'm using locally?

Index: iq2000.h
===================================================================
--- iq2000.h	(revision 114529)
+++ iq2000.h	(working copy)
@@ -518,6 +518,7 @@ typedef struct iq2000_args
 
 #define INITIALIZE_TRAMPOLINE(ADDR, FUNC, CHAIN)			    \
 {									    \
   rtx addr = ADDR;							    \
+  error ("trampolines are not supported on iq2000");			    \
     emit_move_insn (gen_rtx_MEM (SImode, plus_constant (addr, 32)), FUNC); \
     emit_move_insn (gen_rtx_MEM (SImode, plus_constant (addr, 36)), CHAIN);\