to select the right format string (at compile time) when displaying
variables of type db_expr_t.
This fixes a problem where ddb(4) would only display the low 32-bits
of registers for an ILP32 kernel on SH5, even though registers
(and db_expr_t) are always 64-bits wide.
Make some variables and functions static when not used outside of a module.
Make variables in headers extern.
Delete the unused db_find_watchpoint() function.
important as db_sym() can be called through printf() rather than
db_printf(), causing a trap as the standard %n usage is invoked.
The DDB-specific %n code should disappear from subr_prf.c soon...
scw