#define cdiag_width 16
#define cdiag_height 16
-static char cdiag_bits[] = {
+static unsigned char cdiag_bits[] = {
0x81, 0x81, 0x42, 0x42, 0x24, 0x24, 0x18, 0x18, 0x18, 0x18, 0x24, 0x24,
0x42, 0x42, 0x81, 0x81, 0x81, 0x81, 0x42, 0x42, 0x24, 0x24, 0x18, 0x18,
0x18, 0x18, 0x24, 0x24, 0x42, 0x42, 0x81, 0x81};