Raise the WARNS level in cddl/lib
cddl/lib/libavl/Makefile
cddl/lib/libctf/Makefile
cddl/lib/libnvpair/Makefile
cddl/lib/libumem/Makefile
cddl/lib/libuutil/Makefile
Increase WARNS to the highest working level for each of these
libraries
Approved by: re (gjb, hrs)
MFC after: 4 weeks
Sponsored by: Spectra Logic Corp