prog.c: In function ‘cmp’:
prog.c:9:28: error: initialization discards ‘const’ qualifier from pointer target type [-Werror=discarded-qualifiers]
const char (*ps1)[255] = p1;
^~
prog.c:10:28: error: initialization discards ‘const’ qualifier from pointer target type [-Werror=discarded-qualifiers]
const char (*ps2)[255] = p2;
^~
cc1: all warnings being treated as errors