Pull up following revision(s) (requested by kamil in ticket #872):

external/bsd/top/dist/machine/m_netbsd.c: revision 1.20

Fix read of unitialized array elements in top(1)

The cp_old array is allocated with malloc(3) and its pointer is passed to=
percentages64().

In this function there happens a calculation of total_change, which value=
depends on the value inside the unitialized cp_old[] array.

WARNING: MemorySanitizer: use-of-uninitialized-value
/usr/src/external/bsd/top/bin/../dist/machine/m_netbsd.c:1341:6
/usr/src/external/bsd/top/bin/../dist/machine/m_netbsd.c:478:65
SUMMARY: MemorySanitizer: use-of-uninitialized-value
/usr/src/external/bsd/top/bin/../dist/machine/m_netbsd.c:1341:6 in percentages64
Exiting

Fix this issue by changling malloc(3) with calloc(3).

Detected with Memory Sanitizer during the integration of sanitizers with
the NetBSD basesystem.

Reported by <Yang Zheng>

(martin)