The if (c >= 20 && c <= 0x3f) test added in commit 7a99565f8732 is
wrong. 20 is DC4 in ascii and it makes no sense to consider that as the
bottom limit. Instead, it should be 0x20 as in the other test in
the commit above. This is supposed to NOT change anything as we handle
interesting 20-0x20 asciis far before this if.