diff --git a/game/boe.main.cpp b/game/boe.main.cpp
index 24cb21f5..445d1422 100644
--- a/game/boe.main.cpp
+++ b/game/boe.main.cpp
@@ -18,6 +18,24 @@
 
 #include "globvar.h"
 
+// Check windows
+#if _WIN32 || _WIN64
+#if _WIN64
+#define ENVIRONMENT64
+#else
+#define ENVIRONMENT32
+#endif
+#endif
+
+// Check GCC
+#if __GNUC__
+#if __x86_64__ || __ppc64__
+#define ENVIRONMENT64
+#else
+#define ENVIRONMENT32
+#endif
+#endif
+
 void startup_load()
 {
 	load_file();
diff --git a/game/tools/dlogtool.cpp b/game/tools/dlogtool.cpp
index 638b9c8a..55a6689e 100644
--- a/game/tools/dlogtool.cpp
+++ b/game/tools/dlogtool.cpp
@@ -47,7 +47,12 @@ short item_label_loc[NI];
 
 inline void cd_kill_dc(short which_slot,HDC hdc) { fry_dc(dlgs[which_slot],hdc); }
 
-LRESULT CALLBACK dummy_dialog_proc(HWND hDlg, UINT message, WPARAM wParam, LPARAM lParam);
+#ifdef ENVIRONMENT64
+LRESULT
+#else
+BOOL
+#endif
+CALLBACK dummy_dialog_proc(HWND hDlg, UINT message, WPARAM wParam, LPARAM lParam);
 LRESULT CALLBACK fresh_edit_proc(HWND hwnd, UINT message, WPARAM wParam, LPARAM lParam);
 
 LRESULT CALLBACK WndProc (HWND, UINT, WPARAM, LPARAM);
@@ -542,7 +547,12 @@ short cd_create_dialog(short dlog_num, HWND parent)
 	return 0;
 }
 
-LRESULT CALLBACK dummy_dialog_proc (HWND hDlg, UINT message, WPARAM, LPARAM)
+#ifdef ENVIRONMENT64
+LRESULT
+#else
+BOOL
+#endif
+CALLBACK dummy_dialog_proc (HWND hDlg, UINT message, WPARAM, LPARAM)
 {
 	short i,j,k,free_slot = -1,free_item = -1;
 	int type, flag;