setmnotwielded should always MON_NOWEP

Instead of making the caller remember to use MON_NOWEP, make
setmnotwielded handle that automatically.  This fixes the
"bad monster weapon restore" errors I've been seeing.

Also adds sanity checks for this.

src/dig.c

@@ -1973,10 +1973,8 @@ long timeout; /* unused */
             stop_occupation();
         }
     } else if (obj->where == OBJ_MINVENT && obj->owornmask) {
-        if (obj == MON_WEP(obj->ocarry)) {
+        if (obj == MON_WEP(obj->ocarry))
             setmnotwielded(obj->ocarry, obj);
-            MON_NOWEP(obj->ocarry);
-        }
     } else if (obj->where == OBJ_MIGRATING) {
         /* clear destination flag so that obfree()'s check for
            freeing a worn object doesn't get a false hit */

src/mkobj.c

@@ -2156,9 +2156,16 @@ struct monst *monlist;
 const char *mesg;
 {
     struct monst *mon;
-    struct obj *obj;
+    struct obj *obj, *mwep;
 
-    for (mon = monlist; mon; mon = mon->nmon)
+    for (mon = monlist; mon; mon = mon->nmon) {
+        mwep = MON_WEP(mon);
+        if (mwep) {
+            if (!mcarried(mwep))
+                insane_object(mwep, mfmt1, mesg, mon);
+            if (mwep->ocarry != mon)
+                insane_object(mwep, mfmt2, mesg, mon);
+        }
         for (obj = mon->minvent; obj; obj = obj->nobj) {
             if (obj->where != OBJ_MINVENT)
                 insane_object(obj, mfmt1, mesg, mon);
@@ -2166,6 +2173,7 @@ const char *mesg;
                 insane_object(obj, mfmt2, mesg, mon);
             check_contained(obj, mesg);
         }
+    }
 }
 
 /* This must stay consistent with the defines in obj.h. */

src/mthrowu.c

@@ -282,10 +282,8 @@ struct obj *obj;         /* missile (or stack providing it) */
 
         /* not possibly_unwield, which checks the object's */
         /* location, not its existence */
-        if (MON_WEP(mon) == obj) {
+        if (MON_WEP(mon) == obj)
             setmnotwielded(mon, obj);
-            MON_NOWEP(mon);
-        }
         obj_extract_self(obj);
         singleobj = obj;
         obj = (struct obj *) 0;

src/uhitm.c

@@ -670,7 +670,6 @@ int thrown; /* HMON_xxx (0 => hand-to-hand, other => ranged) */
                      * the percentage chance is (1/20)*(50/100).]
                      */
                     setmnotwielded(mon, monwep);
-                    MON_NOWEP(mon);
                     mon->weapon_check = NEED_WEAPON;
                     pline("%s from the force of your blow!",
                           Yobjnam2(monwep, "shatter"));
@@ -1349,10 +1348,8 @@ struct attack *mattk;
         obj_extract_self(otmp);
         if ((unwornmask = otmp->owornmask) != 0L) {
             mdef->misc_worn_check &= ~unwornmask;
-            if (otmp->owornmask & W_WEP) {
+            if (otmp->owornmask & W_WEP)
                 setmnotwielded(mdef, otmp);
-                MON_NOWEP(mdef);
-            }
             otmp->owornmask = 0L;
             update_mon_intrinsics(mdef, otmp, FALSE, FALSE);
 

src/weapon.c

@@ -582,7 +582,6 @@ boolean polyspot;
     }
     if (!attacktype(mon->data, AT_WEAP)) {
         setmnotwielded(mon, mw_tmp);
-        MON_NOWEP(mon);
         mon->weapon_check = NO_WEAPON_WANTED;
         obj_extract_self(obj);
         if (cansee(mon->mx, mon->my)) {
@@ -735,7 +734,6 @@ struct monst *mon;
 
     if (mwep) {
         setmnotwielded(mon, mwep);
-        MON_NOWEP(mon);
         mon->weapon_check = NEED_WEAPON;
     }
 }
@@ -1443,6 +1441,8 @@ register struct obj *obj;
                   s_suffix(mon_nam(mon)), mbodypart(mon, HAND),
                   otense(obj, "stop"));
     }
+    if (MON_WEP(mon) == obj)
+        MON_NOWEP(mon);
     obj->owornmask &= ~W_WEP;
 }