Hi,

'gdbarch_dump' is in some cases passing a NULL pointer to 'sprintf' when 
printing 'gdbarch->stap_gdb_register_suffix' etc.  Printing NULL 
pointers like this is undefined behavior.  With glibc passing a NULL 
pointer just prints "(null)". With the MSVC libc, however, GDB crashes.

Attached patch fixes this issue using the similar approach discussed in 
following scenario:
http://sourceware.org/ml/gdb-patches/2011-10/msg00662.html

There are some newly added variables due to which "maint print arch" 
command was causing gdb crash on whindows host. This patch takes care of 
them.

OK?

Thanks,
-Ali