Update qdb_get_string's mangling for qfcc's new unsigned int support and
fix an incorrect cast of the param pointer passed by prd_runerror that
caused a segfault when trying to use the string. Attempting to use
qwaq-app (ie, the qc debugger) on Ruamoko ISA progs mostly works, but
the defs are decidedly unhappy (due to the base registers).
f72e8ef551