diff --git a/saveload.c b/saveload.c
index 39e3d2591c..4a5470cb95 100644
--- a/saveload.c
+++ b/saveload.c
@@ -722,7 +722,7 @@ void SlObject(void *object, const SaveLoad *sld)
 	}
 
 	for (; sld->cmd != SL_END; sld++) {
-		void *ptr = (byte*)object + (unsigned long)sld->address;
+		void *ptr = (byte*)object + (ptrdiff_t)sld->address;
 		SlObjectMember(ptr, sld);
 	}
 }
diff --git a/settings.h b/settings.h
index 1c95601da1..d8d83c6e29 100644
--- a/settings.h
+++ b/settings.h
@@ -71,7 +71,7 @@ typedef enum {
  * to add this to the address of the object */
 static inline void *ini_get_variable(const SaveLoad *sld, const void *object)
 {
-	return (object == NULL) ? sld->address : (byte*)object + (unsigned long)sld->address;
+	return (object == NULL) ? sld->address : (byte*)object + (ptrdiff_t)sld->address;
 }
 
 void IConsoleSetPatchSetting(const char *name, const char *value);
diff --git a/stdafx.h b/stdafx.h
index 21444ef703..a8600d9b58 100644
--- a/stdafx.h
+++ b/stdafx.h
@@ -3,6 +3,7 @@
 #ifndef STDAFX_H
 #define STDAFX_H
 
+#include <stddef.h>
 #include <stdio.h>
 #include <string.h>
 #include <stdlib.h>