Merge upstream fix to eliminate build-breaking gcc warnings of no
importance.
commit: cab33b7a0acba7d2268a23c4383be6167106e549
Update ND_TTEST2 to fix issue 443
Add IS_NOT_NEGATIVE macro.
Avoid these warnings:
- comparison of unsigned expression >= 0 is always true [-Wtype-limits],
- comparison is always true due to limited range of data type [-Wtype-limits].
Reviewed by: adrian
Approved by: jmallett (mentor)
MFC after: 1 month
358fd7dabb