Preprocessor fixes (#if DEBUG -> #ifdef DEBUG).

Author: tamlin-mike

src/xrCore/ptmalloc3/malloc.c

@@ -2957,7 +2957,7 @@ static int change_mparam(int param_number, int value) {
   }
 }
 
-#if DEBUG
+#ifdef DEBUG
 /* ------------------------- Debugging Support --------------------------- */
 
 /* Check properties of any chunk, whether free, inuse, mmapped etc  */
@@ -4456,7 +4456,7 @@ static void** ialloc(mstate m,
     }
   }
 
-#if DEBUG
+#ifdef DEBUG
   if (marray != chunks) {
     /* final element must have exactly exhausted chunk */
     if (element_size != 0) {

src/xrGame/LevelGraphDebugRender.cpp

@@ -8,7 +8,7 @@
 
 #include "stdafx.h"
 #include "LevelGraphDebugRender.hpp"
-#if DEBUG
+#ifdef DEBUG
 #include "xrAICore/Navigation/game_graph.h"
 #include "xrAICore/Navigation/level_graph.h"
 #include "xrAICore/Navigation/graph_engine.h"

src/xrGame/LevelGraphDebugRender.hpp

@@ -1,5 +1,5 @@
 #pragma once
-#if DEBUG
+#ifdef DEBUG
 #include "xrCore/xrCore.h"
 #include "Include/xrRender/DebugShader.h"
 class CGameGraph;