Compiling src/mess/tools/imgtool/modules/psion.c...
src/mess/tools/imgtool/modules/psion.c:414:15: error: read-only variable is not assignable
        pack_head[0] |= (option_resolution_lookup_int(opts, 'R')) ? 0x00 : 0x02;
        ~~~~~~~~~~~~ ^
src/mess/tools/imgtool/modules/psion.c:415:15: error: read-only variable is not assignable
        pack_head[0] |= (option_resolution_lookup_int(opts, 'P')) ? 0x04 : 0x00;
        ~~~~~~~~~~~~ ^
src/mess/tools/imgtool/modules/psion.c:416:15: error: read-only variable is not assignable
        pack_head[0] |= (option_resolution_lookup_int(opts, 'W')) ? 0x00 : 0x08;
        ~~~~~~~~~~~~ ^
src/mess/tools/imgtool/modules/psion.c:417:15: error: read-only variable is not assignable
        pack_head[0] |= (option_resolution_lookup_int(opts, 'B')) ? 0x00 : 0x10;
        ~~~~~~~~~~~~ ^
src/mess/tools/imgtool/modules/psion.c:418:15: error: read-only variable is not assignable
        pack_head[0] |= (option_resolution_lookup_int(opts, 'C')) ? 0x20 : 0x00;
        ~~~~~~~~~~~~ ^
src/mess/tools/imgtool/modules/psion.c:419:15: error: read-only variable is not assignable
        pack_head[1] = option_resolution_lookup_int(opts, 'S');
        ~~~~~~~~~~~~ ^
src/mess/tools/imgtool/modules/psion.c:421:13: error: no matching function for call to 'head_checksum'
        checksum = head_checksum(pack_head);
                   ^~~~~~~~~~~~~
src/mess/tools/imgtool/modules/psion.c:50:8: note: candidate function not viable: no known conversion from 'const UINT8 [8]' to 'UINT8 *' (aka 'unsigned char *') for 1st argument
UINT16 head_checksum(UINT8* data)
       ^
7 errors generated.