made it so undead units have a dummy 'undead' trait...

...with a description of the effects of being race undead

data/game.cfg

@@ -481,7 +481,9 @@
 	[race]
 	name=undead
 	not_living=yes
-	num_traits=0
+	num_traits=1
+	ignore_global_traits=yes
+	{TRAIT_UNDEAD}
 	[/race]
 	[race]
 	name=ogre

data/traits.cfg

@@ -2,12 +2,21 @@
 	[trait]
 	id=loyal
 	name= _ "loyal"
+	description= _ "Zero upkeep"
 		[effect]
 		apply_to=loyal
 		[/effect]
 	[/trait]
 #enddef
 
+#define TRAIT_UNDEAD
+	[trait]
+	id=undead
+	name= _ "undead"
+	description= _ "Immune to poison"
+	[/trait]
+#enddef
+
 #define TRAIT_STRONG
 	[trait]
 	id=strong

src/race.cpp

@@ -95,12 +95,13 @@ wide_string markov_generate_name(const markov_prefix_map& prefixes, size_t chain
 
 }
 
-unit_race::unit_race() : ntraits_(0), chain_size_(0), not_living_(false), traits_(&empty_traits)
+unit_race::unit_race() : ntraits_(0), chain_size_(0), not_living_(false), traits_(&empty_traits), global_traits_(true)
 {
 }
 
 unit_race::unit_race(const config& cfg) : name_(cfg["name"]), ntraits_(atoi(cfg["num_traits"].c_str())),
-                                          not_living_(cfg["not_living"] == "yes"), traits_(&cfg.get_children("trait"))
+                                          not_living_(cfg["not_living"] == "yes"),
+										  traits_(&cfg.get_children("trait")), global_traits_(cfg["ignore_global_traits"] != "yes")
 {
 	names_[MALE] = utils::split(cfg["male_names"]);
 	names_[FEMALE] = utils::split(cfg["female_names"]);
@@ -120,6 +121,11 @@ std::string unit_race::generate_name(unit_race::GENDER gender) const
 	return utils::wstring_to_string(markov_generate_name(next_[gender],chain_size_,12));
 }
 
+bool unit_race::uses_global_traits() const
+{
+	return global_traits_;
+}
+
 const config::child_list& unit_race::additional_traits() const
 {
 	return *traits_;

src/race.hpp

@@ -22,6 +22,8 @@ public:
 
 	std::string generate_name(GENDER gender) const;
 
+	bool uses_global_traits() const;
+
 	const config::child_list& additional_traits() const;
 	int num_traits() const;
 
@@ -37,6 +39,7 @@ private:
 	bool not_living_;
 
 	const config::child_list* traits_;
+	bool global_traits_;
 };
 
 typedef std::map<std::string,unit_race> race_map;

src/unit_types.cpp

@@ -581,6 +581,10 @@ unit_type::unit_type(const config& cfg, const movement_type_map& mv_types,
 	if(race_it != races.end()) {
 		race_ = &race_it->second;
 		if(race_ != NULL) {
+			if(race_->uses_global_traits() == false) {
+				possibleTraits_.clear();
+			}
+
 			const config::child_list& traits = race_->additional_traits();
 			possibleTraits_.insert(possibleTraits_.end(),traits.begin(),traits.end());
 		}