crystal armor bit

Accidentally left out of the "breaking crystal armor" commit
e9c58c2fe4.

doc/fixes3-7-0.txt

@@ -2155,6 +2155,7 @@ preceding #overview with the 'm' prefix brings up the overview display as a
 	menu allowing selection of any visited level to #annotate; it also
 	shows every level visited rather than just the "interesting" ones
 include monster size in feedback for wand of probing and stethoscope
+crystal armor is now subject to cracking damage rather than outright breakage
 
 
 Platform- and/or Interface-Specific New Features

src/do_wear.c

@@ -516,24 +516,9 @@ Helmet_off(void)
 boolean
 hard_helmet(struct obj *obj)
 {
-    static const char crystal_[] = "crystal ";
-    const char *ostr;
-    int otyp;
-
     if (!obj || !is_helmet(obj))
         return FALSE;
-    if (is_metallic(obj))
-        return TRUE;
-    /* make helm of brilliance (crystal helmet) be classified 'hard'; this
-       test would work for crystal plate mail too if suits reached here */
-    otyp = obj->otyp;
-    if (objects[otyp].oc_material == GLASS
-        && (((ostr = OBJ_NAME(objects[otyp])) != 0
-             && !strncmp(ostr, crystal_, 8))
-            || ((ostr = OBJ_DESCR(objects[otyp])) != 0
-                && !strncmp(ostr, crystal_, 8))))
-        return TRUE;
-    return FALSE;
+    return (is_metallic(obj) || is_crackable(obj)) ? TRUE : FALSE;
 }
 
 static int