Prefer size_t for buffer sizes and indexing.

src/cdi_across.c

src/cdi_key.c

src/grid.c

src/iterator_fallback.c

src/serialize.h

src/stream.c

src/stream_cdf_i.c

src/stream_cdf_time.c

src/stream_cgribex.c

src/stream_gribapi.c

src/stream_ieg.c

src/stream_record.c

src/varscan.c