- defaulted a few empty constructors.

# Conflicts:
#	src/gamedata/g_mapinfo.h

src/doomdata.h

@@ -439,7 +439,7 @@ struct FPlayerStart
 	DVector3 pos;
 	int16_t angle, type;
 
-	FPlayerStart() { }
+	FPlayerStart() = default;
 	FPlayerStart(const FMapThing *mthing, int pnum)
 	: pos(mthing->pos),
 	  angle(mthing->angle),

src/dthinker.h

@@ -128,9 +128,6 @@ public:
 	FThinkerIterator (const PClass *type, int statnum, DThinker *prev);
 	DThinker *Next (bool exact = false);
 	void Reinit ();
-
-protected:
-	FThinkerIterator() {}
 };
 
 template <class T> class TThinkerIterator : public FThinkerIterator

src/g_level.h

@@ -601,7 +601,7 @@ struct FSkillInfo
 	int Infighting;
 	bool PlayerRespawn;
 
-	FSkillInfo() {}
+	FSkillInfo() = default;
 	FSkillInfo(const FSkillInfo &other)
 	{
 		operator=(other);

src/info.h

@@ -267,7 +267,7 @@ struct FActorInfo
 
 	uint8_t DefaultStateUsage = 0; // state flag defaults for blocks without a qualifier.
 
-	FActorInfo() {}
+	FActorInfo() = default;
 	FActorInfo(const FActorInfo & other)
 	{
 		// only copy the fields that get inherited