#define knightR_m_width 49
#define knightR_m_height 49
-static char knightR_m_bits[] = {
+static unsigned char knightR_m_bits[] = {
0xf8,0xff,0xff,0xff,0xff,0x0f,0xfe,0xf8,0xff,0xff,0xff,0xff,0x0f,0xfe,0xf8,
0xff,0xff,0xff,0xff,0x1f,0xfe,0xf8,0xff,0xff,0xff,0xff,0x1f,0xfe,0x38,0x00,
0x00,0x00,0x00,0x10,0xfe,0x38,0x00,0x00,0x00,0x00,0x10,0xfe,0x38,0x00,0x00,