[autofit] Better fix for conversion specifiers in debug messages. Using `%ld' for pointer differences causes warnings on 32bit platforms. The correct type would be (the relatively new) `%td', however, this is missing on some important platforms. This patch improves the change from 2014-11-28. * src/autofit/afhints.c (AF_INDEX_NUM): Use `int' typecast. Our pointer differences are always sufficiently small. (af_glyph_hints_dump_points, af_glyph_hints_dump_segments, af_glyph_hints_dump_edge): Revert to `%d' and use `AF_INDEX_NUM'.