Fix "gems in apply menu" From a bug report.

include/obj.h

@@ -216,6 +216,12 @@ struct obj {
 			 otmp->otyp == WAX_CANDLE)
 #define MAX_OIL_IN_FLASK 400	/* maximum amount of oil in a potion of oil */
 
+/* special stones */
+#define is_greystone(obj)	((obj)->otyp == LUCKSTONE || \
+				 (obj)->otyp == LOADSTONE || \
+				 (obj)->otyp == FLINT     || \
+				 (obj)->otyp == TOUCHSTONE)
+
 /* Flags for get_obj_location(). */
 #define CONTAINED_TOO	0x1
 #define BURIED_TOO	0x2

src/apply.c

@@ -2519,15 +2519,13 @@ do_break_wand(obj)
     return 1;
 }
 
-boolean uhave_greystone()
+STATIC_OVL boolean
+uhave_greystone()
 {
 	register struct obj *otmp;
 
 	for(otmp = invent; otmp; otmp = otmp->nobj)
-		if(otmp->otyp == LOADSTONE ||
-		   otmp->otyp == FLINT ||
-		   otmp->otyp == LUCKSTONE ||
-		   otmp->otyp == TOUCHSTONE)
+		if(is_greystone(otmp))
 			return TRUE;
 	return FALSE;
 }

src/invent.c

@@ -819,7 +819,8 @@ register const char *let,*word;
 		     /* only applicable potion is oil, and it will only
 			be offered as a choice when already discovered */
 		     (otyp != POT_OIL || !otmp->dknown ||
-		      !objects[POT_OIL].oc_name_known))))
+		      !objects[POT_OIL].oc_name_known))
+		|| (otmp->oclass == GEM_CLASS && !is_greystone(otmp))))
 		|| (!strcmp(word, "invoke") &&
 		    (!otmp->oartifact && !objects[otyp].oc_unique &&
 		     (otyp != FAKE_AMULET_OF_YENDOR || otmp->known) &&