diff --git a/src/d_dehacked.cpp b/src/d_dehacked.cpp
index eb4e2fcd6..d01e9513f 100644
--- a/src/d_dehacked.cpp
+++ b/src/d_dehacked.cpp
@@ -2945,7 +2945,7 @@ void FinishDehPatch ()
 		PClass *subclass = RUNTIME_CLASS(ADehackedPickup)->CreateDerivedClass
 			(typeNameBuilder, sizeof(ADehackedPickup));
 		AActor *defaults2 = GetDefaultByType (subclass);
-		memcpy (defaults2, defaults1, sizeof(AActor));
+		memcpy ((void *)defaults2, (void *)defaults1, sizeof(AActor));
 
 		// Make a copy of the replaced class's state labels 
 		FStateDefinitions statedef;
diff --git a/src/decallib.cpp b/src/decallib.cpp
index c8fe6c593..91827409b 100644
--- a/src/decallib.cpp
+++ b/src/decallib.cpp
@@ -452,7 +452,7 @@ void FDecalLib::ParseDecal (FScanner &sc)
 	decalNum = GetDecalID (sc);
 	sc.MustGetStringName ("{");
 
-	memset (&newdecal, 0, sizeof(newdecal));
+	memset ((void *)&newdecal, 0, sizeof(newdecal));
 	newdecal.PicNum.SetInvalid();
 	newdecal.ScaleX = newdecal.ScaleY = FRACUNIT;
 	newdecal.RenderFlags = RF_WALLSPRITE;
diff --git a/src/thingdef/thingdef_properties.cpp b/src/thingdef/thingdef_properties.cpp
index 61a18b370..7b922df02 100644
--- a/src/thingdef/thingdef_properties.cpp
+++ b/src/thingdef/thingdef_properties.cpp
@@ -433,7 +433,7 @@ DEFINE_PROPERTY(skip_super, 0, Actor)
 		return;
 	}
 
-	memcpy (defaults, GetDefault<AActor>(), sizeof(AActor));
+	memcpy ((void *)defaults, (void *)GetDefault<AActor>(), sizeof(AActor));
 	if (bag.DropItemList != NULL)
 	{
 		FreeDropItemChain (bag.DropItemList);