Without _Unwind_GetIPInfo, it is not possible to unwind correctly 
through signal handlers.  glibc needs this, otherwise cancellation does 
not work.

The attached patch documents this function and makes it part of the ABI. 
  I tried to explain as best as I could why this function is needed, 
without talking about exception handler regions.

The 32-bit ABI will need a similar change.

The second patch is for the Makefile, so that it doesn't ask for input 
on an error.

Thanks,
Florian