Change the tips internal data struct

Previously adding any new tips invalidated saves; now you can have
up to the number of bits in a long without change in savefile.

Invalidates saves.

include/context.h

@@ -168,7 +168,7 @@ struct context_info {
     boolean bypasses;    /* bypass flag is set on at least one fobj */
     boolean door_opened; /* set to true if door was opened during test_move */
     boolean resume_wish; /* game was exited while in wish prompt */
-    boolean tips[NUM_TIPS];
+    unsigned long tips;
     struct dig_info digging;
     struct victual_info victual;
     struct engrave_info engraving;

include/patchlevel.h

@@ -17,7 +17,7 @@
  * Incrementing EDITLEVEL can be used to force invalidation of old bones
  * and save files.
  */
-#define EDITLEVEL 136
+#define EDITLEVEL 137
 
 /*
  * Development status possibilities.

src/hack.c

@@ -1834,8 +1834,8 @@ handle_tip(int tip)
     if (!flags.tips)
         return FALSE;
 
-    if (tip >= 0 && tip < NUM_TIPS && !svc.context.tips[tip]) {
-        svc.context.tips[tip] = TRUE;
+    if (tip >= 0 && tip < NUM_TIPS && !(svc.context.tips & (1 << tip))) {
+        svc.context.tips |= (1 << tip);
         /* the "Tip:" prefix is a hint to use of OPTIONS=!tips to suppress */
         switch (tip) {
         case TIP_ENHANCE:
@@ -1886,7 +1886,7 @@ swim_move_danger(coordxy x, coordxy y)
             || liquid_wall) {
             if (svc.context.nopick) {
                 /* moving with m-prefix */
-                svc.context.tips[TIP_SWIM] = TRUE;
+                svc.context.tips |= (1 << TIP_SWIM);
                 return FALSE;
             } else if (ParanoidSwim || liquid_wall) {
                 You("avoid %s into the %s.",

src/weapon.c

@@ -1330,7 +1330,7 @@ enhance_weapon_skill(void)
     boolean speedy = FALSE;
 
     /* player knows about #enhance, don't show tip anymore */
-    svc.context.tips[TIP_ENHANCE] = TRUE;
+    svc.context.tips |= (1 << TIP_ENHANCE);
 
     if (wizard && y_n("Advance skills without practice?") == 'y')
         speedy = TRUE;