greed 4.4 does not build on NetBSD, due to -Werror. ``` greed.c: In function 'main': greed.c:381:74: error: array subscript has type 'char' [-Werror=char-subscripts] 381 | tolower(*cp)) - | ^ ``` POSIX specifies that ctype(3) functions only should be passed EOF or an unsigned char value, and NetBSD is especially picky about this, see https://man.netbsd.org/ctype.3 The standard workaround is to cast the argument to unsigned char (after making sure it is in the correct range).