I've committed this patch which is a correction for my previous work on 
non-aligned memory reads/writes from GDB. It's too late to handle 
bus::unaligned by retrying one byte at a time in process_set_mem because 
by then the input data is no longer in the input stream. I've moved the 
retry to write_bus_word. For consistency, I've also moved the retry for 
reading from process_get_mem to read_bus_word.

Dave