of copies made by getvec(). This is safe, because the old code made
single copies and always flushed them back into the unit structures
before flushing those.
effect. Replace calls by struct assignment where possible. Replace
clear buffer, copy string to buffer by strncpy(). Use assignment to
clear when that's clearer. Replace overlapping copy through bounce
buffer by memmove(). Replace rest by standard memset() and memcpy().
Also use sizeof() instead of literal array sizes for robustness, and
instead of symbolic array sizes for clarity.
