Sting vs level teleport's "materialize" message

When level teleporting, Sting/Orcrish/Grimtooth would start or stop
glowing based on occupants of the new level before "you materialize
on another level".  That wasn't necessarily incorrect for the glow
stopping but was clearly wrong for it starting.  This fix uses a flag
as a hack to avoid finding and changing all the calls to docrt() and
see_monsters().  It ought to be fixed properly....

src/do.c

@@ -1265,7 +1265,7 @@ boolean at_stairs, falling, portal;
     int l_idx, save_mode;
     NHFILE *nhfp;
     xchar new_ledger;
-    boolean cant_go_back, great_effort,
+    boolean cant_go_back, great_effort, materializing,
             up = (depth(newlevel) < depth(&u.uz)),
             newdungeon = (u.uz.dnum != newlevel->dnum),
             was_in_W_tower = In_W_tower(u.ux, u.uy, &u.uz),
@@ -1613,9 +1613,15 @@ boolean at_stairs, falling, portal;
     else if (Is_firelevel(&u.uz))
         fumaroles();
 
+    /* to control message sequencing hack for Sting_effects() */
+    materializing = (g.dfr_post_msg
+                     && !strncmpi(g.dfr_post_msg, "You materialize", 15));
+
     /* Reset the screen. */
     vision_reset(); /* reset the blockages */
     g.glyphmap_perlevel_flags = 0L; /* force per-level mapglyph() changes */
+    if (materializing)
+        iflags.no_glow++; /* to suppress see_monster()'s Sting_effects() */
     docrt();        /* does a full vision recalc */
     flush_screen(-1);
 
@@ -1625,9 +1631,12 @@ boolean at_stairs, falling, portal;
 
     /* deferred arrival message for level teleport looks odd if given
        after the various messages below so give it before them */
-    if (g.dfr_post_msg && !strncmpi(g.dfr_post_msg, "You materialize", 15)) {
+    if (materializing) {
         pline("%s", g.dfr_post_msg);
         free((genericptr_t) g.dfr_post_msg), g.dfr_post_msg = 0;
+
+        iflags.no_glow--;
+        see_monsters(); /* docrt() did this but we need to repeat it */
     }
 
     /* special levels can have a custom arrival message */