Make multiple KMASK lines for the same glyph work (qw)

It turns out that the later mask was overriding the earlier one.
Instead, combine the masks.  Resolve conflicts (no_monster_gen versus
!no_monster_gen for example) in favour of the later mask.

In particular, this allows grunt_temple_overflow_order_and_chaos_1
to place again; it was broken by 0.16-a0-179-g90b15e8.

Thanks to elliptic and gammafunk for helping find and debug the problem.

2 files changed, 14 insertions, 1 deletions

diff --git a/crawl-ref/source/mapdef.cc b/crawl-ref/source/mapdef.cc
index c46b6a58cf..0ef583e43a 100644
--- a/crawl-ref/source/mapdef.cc
+++ b/crawl-ref/source/mapdef.cc
@@ -5792,6 +5792,18 @@ void map_flags::clear()
     flags_set = flags_unset = 0;
 }
 
+map_flags &map_flags::operator |= (const map_flags &o)
+{
+    flags_set |= o.flags_set;
+    flags_unset |= o.flags_unset;
+
+    // In the event of conflict, the later flag set (o here) wins.
+    flags_set &= ~o.flags_unset;
+    flags_unset &= ~o.flags_set;
+
+    return *this;
+}
+
 typedef map<string, unsigned long> flag_map;
 
 map_flags map_flags::parse(const string flag_list[],
@@ -6059,7 +6071,7 @@ string keyed_mapspec::set_mask(const string &s, bool garbage)
             {"vault", "no_item_gen", "no_monster_gen", "no_pool_fixup",
              "UNUSED",
              "no_wall_fixup", "opaque", "no_trap_gen", ""};
-        map_mask = map_flags::parse(flag_list, s);
+        map_mask |= map_flags::parse(flag_list, s);
     }
     catch (const string &error)
     {
diff --git a/crawl-ref/source/mapdef.h b/crawl-ref/source/mapdef.h
index c48e59671b..d005cd5dff 100644
--- a/crawl-ref/source/mapdef.h
+++ b/crawl-ref/source/mapdef.h
@@ -842,6 +842,7 @@ struct map_flags
 
     map_flags();
     void clear();
+    map_flags &operator |= (const map_flags &o);
 
     static map_flags parse(const string flag_list[],
                            const string &s) throw(string);