Pack data structs

src/common.h

@@ -3,11 +3,11 @@
 struct pixel {
 	int x, y;
 	uint8_t bright;
-};
+} __attribute__((packed));
 
 struct packet {
 	uint8_t cmd;
 	union {
 		struct pixel pixel;
 	};
-};
+} __attribute__((packed));