grammar: "foo based" to "foo-based"

There seems to be a need to locate these in the distribution every decade or so.

src/dog.c

@@ -1016,7 +1016,7 @@ dogfood(struct monst *mon, struct obj *obj)
             return ACCFOOD;
         if (metallivorous(mptr) && is_metallic(obj)
             && (is_rustprone(obj) || mptr != &mons[PM_RUST_MONSTER])) {
-            /* Non-rustproofed ferrous based metals are preferred. */
+            /* Non-rustproofed ferrous-based metals are preferred. */
             return (is_rustprone(obj) && !obj->oerodeproof) ? DOGFOOD
                                                             : ACCFOOD;
         }

src/mcastu.c

@@ -70,7 +70,7 @@ cursetxt(struct monst *mtmp, boolean undirected)
     }
 }
 
-/* convert a level based random selection into a specific mage spell;
+/* convert a level-based random selection into a specific mage spell;
    inappropriate choices will be screened out by spell_would_be_useless() */
 static int
 choose_magic_spell(int spellval)
@@ -124,7 +124,7 @@ choose_magic_spell(int spellval)
     }
 }
 
-/* convert a level based random selection into a specific cleric spell */
+/* convert a level-based random selection into a specific cleric spell */
 static int
 choose_clerical_spell(int spellnum)
 {

src/polyself.c

@@ -339,7 +339,7 @@ newman(void)
 
     /*
      * New hit points:
-     *  remove level-gain based HP from any extra HP accumulated
+     *  remove "level gain"-based HP from any extra HP accumulated
      *  (the "extra" might actually be negative);
      *  modify the extra, retaining {80%, 90%, 100%, or 110%};
      *  add in newly generated set of level-gain HP.

src/vision.c

@@ -478,7 +478,7 @@ new_angle(struct rm *lev, unsigned char *sv, int row, int col)
  *      + After the monster move, before input from the player. [moveloop()]
  *      + At end of moveloop. [moveloop() ??? not sure why this is here]
  *      + Right before something is printed. [pline()]
- *      + Right before we do a vision based operation. [do_clear_area()]
+ *      + Right before we do a vision-based operation. [do_clear_area()]
  *      + screen redraw, so we can renew all positions in sight. [docrt()]
  *      + When toggling temporary blindness, in case additional events
  *        impacted by vision occur during the same move [make_blinded()]