Added INFLICTORDMGTYPE flag to A_Damage* action functions

It forces the use of the inflictor's damagetype instead of whatever is
passed to the functions.

src/thingdef/thingdef_codeptr.cpp

@@ -6129,6 +6129,7 @@ enum DMSS
 	DMSS_EXFILTER			= 64,	//Changes filter into a blacklisted class instead of whitelisted.
 	DMSS_EXSPECIES			= 128,	// ^ but with species instead.
 	DMSS_EITHER				= 256,  //Allow either type or species to be affected.
+	DMSS_INFLICTORDMGTYPE	= 512,	//Ignore the passed damagetype and use the inflictor's instead.
 };
 
 static void DoDamage(AActor *dmgtarget, AActor *inflictor, AActor *source, int amount, FName DamageType, int flags, PClassActor *filter, FName species)
@@ -6153,6 +6154,9 @@ static void DoDamage(AActor *dmgtarget, AActor *inflictor, AActor *source, int a
 	
 		if (amount > 0)
 		{ //Should wind up passing them through just fine.
+			if (flags & DMSS_INFLICTORDMGTYPE)
+				DamageType = inflictor->DamageType;
+
 			P_DamageMobj(dmgtarget, inflictor, source, amount, DamageType, dmgFlags);
 		}
 		else if (amount < 0)

wadsrc/static/actors/constants.txt

@@ -466,6 +466,7 @@ enum
 	DMSS_EXFILTER =			0x00000040,
 	DMSS_EXSPECIES =		0x00000080,
 	DMSS_EITHER =			0x00000100,
+	DMSS_INFLICTORDMGTYPE =	0x00000200,
 };
 
 // Flags for A_AlertMonsters