All NCEPLIBS code must build without warnings with GNU and -Wall

[edwardhartnett]

As it says in the NCO code standards (https://www.nco.ncep.noaa.gov/idsb/implementation_standards/):

Code must compile without errors and warnings

This is excellent guidance. Warnings are one of the cheapest and easiest ways to find bugs, but only work if we ruthlessly stamp them out every time they appear.

There are many compiler warnings in the NCEPLIBS and UFS_UTILS code. We need to fix them all.