Fix clang15 warnings

src/cdi.h

src/cdi_query.c

src/extralib.c

src/file.c

src/gribapi.h

src/gribapi_utilities.c

src/namespace.c

src/resource_handle.c

src/stream_cgribex.c

src/stream_cgribex.h

src/table.c

src/vlist_var_key.c

tests/cksum_verify.c

tests/test_byteswap.c

tests/test_grib.c

tests/test_resource_copy.c

tests/test_table.c