make all file/network-related structs packed

src/RareItemSet.hh

@@ -7,9 +7,10 @@
 struct RareItemDrop {
   uint8_t probability;
   uint8_t item_code[3];
-};
+} __attribute__((packed));
 
 struct RareItemSet {
+  // 0x280 in size; describes one difficulty, section ID, and episode
   RareItemDrop rares[0x65];     // 0000 - 0194 in file
   uint8_t box_areas[0x1E];      // 0194 - 01B2 in file
   RareItemDrop box_rares[0x1E]; // 01B2 - 022A in file
@@ -17,6 +18,6 @@ struct RareItemSet {
 
   RareItemSet(const char* filename, uint8_t episode, uint8_t difficulty,
   	  uint8_t secid);
-}; // 0x280 in size; describes one difficulty, section ID, and episode
+} __attribute__((packed));
 
 bool sample_rare_item(uint8_t pc);