Hello,

At present unwind sniffers are appeneded to the search list. 
Consequently to ensure that the more specific OSABI unwinders override 
the more generic architecture unwinders, the architecture code has to 
append the sniffers in reverse order.

This is contrary to how the rest of the architecture vector is 
constructed - for other architecture entries, the OSABI does its 
initialization last, overriding earlier more generic architecture entries.

The attached replaces the recently added, and hardly called,
rame_unwind_register_unwinder (which does an append) with 
frame_unwind_prepend_unwinder (which does a prepend).

By using this new method, OSABI code can ensure that their methods are 
always at the front of the unwind sniffer search list, and hence ensure 
that their methods always override the more generic architecture methods.

Comments?  I'll leave this for a few days.
Andrew