proposal for link age macros (#1119)

* proposal for link age macros

* apply @Dragorn421 suggestions

* also annotate the slinkage variable

include/z64save.h

@@ -62,7 +62,7 @@ typedef struct {
 
 typedef struct {
     /* 0x0000 */ s32 entranceIndex; // start of `save` substruct, originally called "memory"
-    /* 0x0004 */ s32 linkAge; // 0: Adult; 1: Child
+    /* 0x0004 */ s32 linkAge;
     /* 0x0008 */ s32 cutsceneIndex;
     /* 0x000C */ u16 dayTime; // "zelda_time"
     /* 0x0010 */ s32 nightFlag;
@@ -212,4 +212,9 @@ typedef enum {
     /* 3 */ SUNSSONG_SPECIAL // time does not advance, but signals the song was played. used for freezing redeads
 } SunsSongState;
 
+typedef enum {
+    /* 0 */ LINK_AGE_ADULT,
+    /* 1 */ LINK_AGE_CHILD
+} LinkAge;
+
 #endif