Split out the non-ARM specific portions of SYS_SEEK to a
reusable function. This handles all GuestFD. Isolate the
curious ARM-specific return value processing to a new
callback, common_semi_seek_cb.
Expand the internal type of the offset to int64_t, and
provide the whence argument, which will be required by
m68k and nios2 semihosting.
Note that gdb_do_syscall %x reads target_ulong, not int.
Reviewed-by: Luc Michel <lmichel@kalray.eu>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
9a89470449