diff --git a/Makefile.src.in b/Makefile.src.in
index 06d6f43b72..8c9e4a8f83 100644
--- a/Makefile.src.in
+++ b/Makefile.src.in
@@ -35,9 +35,9 @@ CONFIG_CACHE_VERSION  = $(SRC_OBJS_DIR)/!!CONFIG_CACHE_VERSION!!
 
 OBJS_C   := !!OBJS_C!!
 OBJS_CPP := !!OBJS_CPP!!
-OBJS_M   := !!OBJS_M!!
+OBJS_MM  := !!OBJS_MM!!
 OBJS_RC  := !!OBJS_RC!!
-OBJS     := $(OBJS_C) $(OBJS_CPP) $(OBJS_M) $(OBJS_RC)
+OBJS     := $(OBJS_C) $(OBJS_CPP) $(OBJS_MM) $(OBJS_RC)
 SRCS     := !!SRCS!!
 
 # All C-files depend on those 3 files
@@ -126,12 +126,12 @@ $(OBJS_CPP:%.o=%.d): %.d: $(SRC_DIR)/%.cpp $(FILE_DEP)
 	$(E) '$(STAGE) DEP $(<:$(SRC_DIR)/%.cpp=%.cpp)'
 	$(Q)$(CXX_HOST) $(CFLAGS) -MM $< | sed 's#^$(@F:%.d=%.o):#$@ $(@:%.d=%.o):#' > $@
 
-$(OBJS_M:%.o=%.d): %.d: $(SRC_DIR)/%.m $(FILE_DEP)
-	$(E) '$(STAGE) DEP $(<:$(SRC_DIR)/%.m=%.m)'
-	$(Q)$(CC_HOST) $(CC_CFLAGS) $(CFLAGS) -MM $< | sed 's#^$(@F:%.d=%.o):#$@ $(@:%.d=%.o):#' > $@
+$(OBJS_MM:%.o=%.d): %.d: $(SRC_DIR)/%.mm $(FILE_DEP)
+	$(E) '$(STAGE) DEP $(<:$(SRC_DIR)/%.mm=%.mm)'
+	$(Q)$(CC_HOST) $(CFLAGS) -MM $< | sed 's#^$(@F:%.d=%.o):#$@ $(@:%.d=%.o):#' > $@
 
 $(OBJS_RC:%.o=%.d): %.d: $(SRC_DIR)/%.rc $(FILE_DEP)
-	$(E) '$(STAGE) DEP $(<:$(SRC_DIR)/%.m=%.m)'
+	$(E) '$(STAGE) DEP $(<:$(SRC_DIR)/%.mm=%.mm)'
 	$(Q)touch $@
 
 else
@@ -211,9 +211,9 @@ $(OBJS_CPP): %.o: $(SRC_DIR)/%.cpp $(DEP_MASK) $(FILE_DEP)
 	$(E) '$(STAGE) Compiling $(<:$(SRC_DIR)/%.cpp=%.cpp)'
 	$(Q)$(CXX_HOST) $(CFLAGS) -c -o $@ $<
 
-$(OBJS_M): %.o: $(SRC_DIR)/%.m $(DEP_MASK) $(FILE_DEP)
-	$(E) '$(STAGE) Compiling $(<:$(SRC_DIR)/%.m=%.m)'
-	$(Q)$(CC_HOST) $(CC_CFLAGS) $(CFLAGS) -c -o $@ $<
+$(OBJS_MM): %.o: $(SRC_DIR)/%.mm $(DEP_MASK) $(FILE_DEP)
+	$(E) '$(STAGE) Compiling $(<:$(SRC_DIR)/%.mm=%.mm)'
+	$(Q)$(CC_HOST) $(CFLAGS) -c -o $@ $<
 
 $(OBJS_RC): %.o: $(SRC_DIR)/%.rc $(FILE_DEP)
 	$(E) '$(STAGE) Compiling resource $(<:$(SRC_DIR)/%.rc=%.rc)'
diff --git a/config.lib b/config.lib
index 804de5223b..9189c30f9a 100644
--- a/config.lib
+++ b/config.lib
@@ -1639,7 +1639,7 @@ make_sed() {
 		s#!!LANG_SUPPRESS!!#$lang_suppress#g;
 		s#!!OBJS_C!!#$OBJS_C#g;
 		s#!!OBJS_CPP!!#$OBJS_CPP#g;
-		s#!!OBJS_M!!#$OBJS_M#g;
+		s#!!OBJS_MM!!#$OBJS_MM#g;
 		s#!!OBJS_RC!!#$OBJS_RC#g;
 		s#!!SRCS!!#$SRCS#g;
 		s#!!OS!!#$os#g;
diff --git a/configure b/configure
index 43f7347c95..c79bd606cc 100755
--- a/configure
+++ b/configure
@@ -100,7 +100,7 @@ SRCS="`< $ROOT_DIR/source.list tr '\r' '\n' | awk '
 
 OBJS_C="`  echo \"$SRCS\" | awk ' { ORS = " " } /\.c$/   { gsub(".c$",   ".o", $0); print $0; }'`"
 OBJS_CPP="`echo \"$SRCS\" | awk ' { ORS = " " } /\.cpp$/ { gsub(".cpp$", ".o", $0); print $0; }'`"
-OBJS_M="`  echo \"$SRCS\" | awk ' { ORS = " " } /\.m$/   { gsub(".m$",   ".o", $0); print $0; }'`"
+OBJS_MM="` echo \"$SRCS\" | awk ' { ORS = " " } /\.mm$/  { gsub(".mm$",  ".o", $0); print $0; }'`"
 OBJS_RC="` echo \"$SRCS\" | awk ' { ORS = " " } /\.rc$/  { gsub(".rc$",  ".o", $0); print $0; }'`"
 SRCS="`    echo \"$SRCS\" | awk ' { ORS = " " } { print $0; }'`"
 
diff --git a/source.list b/source.list
index 5966fa0db1..e13d597e8d 100644
--- a/source.list
+++ b/source.list
@@ -384,7 +384,7 @@ sound/null_s.cpp
 
 #if OSX
 # OSX Files
-	os/macosx/macos.m
+	os/macosx/macos.mm
 
 	#if DEDICATED
 	#else
@@ -392,7 +392,7 @@ sound/null_s.cpp
 	#end
 
 	#if COCOA
-		video/cocoa_v.m
+		video/cocoa_v.mm
 		sound/cocoa_s.cpp
 		os/macosx/splash.cpp
 	#end
diff --git a/src/debug.h b/src/debug.h
index 0e58dfdce6..47d7855f9d 100644
--- a/src/debug.h
+++ b/src/debug.h
@@ -3,10 +3,6 @@
 #ifndef DEBUG_H
 #define DEBUG_H
 
-#ifdef __cplusplus
-extern "C" {
-#endif //__cplusplus
-
 /* Debugging messages policy:
  * These should be the severities used for direct DEBUG() calls
  * maximum debugging level should be 10 if really deep, deep
@@ -111,8 +107,4 @@ const char *GetDebugString(void);
 	}\
 }
 
-#ifdef __cplusplus
-}
-#endif //__cplusplus
-
 #endif /* DEBUG_H */
diff --git a/src/gfx.h b/src/gfx.h
index 2316e8e86f..3c3cc7f310 100644
--- a/src/gfx.h
+++ b/src/gfx.h
@@ -3,11 +3,6 @@
 #ifndef GFX_H
 #define GFX_H
 
-/* !!! Note that the first part of this file if enclosed in extern "C" due to cocoa/obj-C !!! */
-
-#ifdef __cplusplus
-extern "C" {
-#endif /* __cplusplus */
 
 enum WindowKeyCodes {
 	WKC_SHIFT = 0x8000,
@@ -175,10 +170,6 @@ void HandleExitGameRequest(void);
 void GameSizeChanged(void);
 void UndrawMouseCursor(void);
 
-#ifdef __cplusplus
-}; //extern "C"
-/* Following part is only for C++ */
-
 #include "helpers.hpp"
 
 typedef enum FontSizes {
@@ -245,7 +236,7 @@ void ScreenSizeChanged(void);
 void UndrawMouseCursor(void);
 bool ChangeResInGame(int w, int h);
 void SortResolutions(int count);
-extern "C" void ToggleFullScreen(bool fs);
+void ToggleFullScreen(bool fs);
 
 /* gfx.c */
 #define ASCII_LETTERSTART 32
@@ -301,6 +292,4 @@ typedef enum StringColorFlags {
 extern bool _dbg_screen_rect;
 #endif
 
-#endif /* __cplusplus */
-
 #endif /* GFX_H */
diff --git a/src/hal.h b/src/hal.h
index e3d051c25e..0729c6c99f 100644
--- a/src/hal.h
+++ b/src/hal.h
@@ -3,10 +3,6 @@
 #ifndef HAL_H
 #define HAL_H
 
-#ifdef __cplusplus
-extern "C" {
-#endif //__cplusplus
-
 typedef struct {
 	const char *(*start)(const char * const *parm);
 	void (*stop)(void);
@@ -46,8 +42,4 @@ enum DriverType {
 	MUSIC_DRIVER = 2,
 };
 
-#ifdef __cplusplus
-} // extern "C"
-#endif //__cplusplus
-
 #endif /* HAL_H */
diff --git a/src/md5.h b/src/md5.h
index 6e1f3044b3..c3c8888d92 100644
--- a/src/md5.h
+++ b/src/md5.h
@@ -72,11 +72,6 @@ typedef struct md5_state_s {
     md5_byte_t buf[64];  /* accumulate block */
 } md5_state_t;
 
-#ifdef __cplusplus
-extern "C"
-{
-#endif
-
 /* Initialize the algorithm. */
 void md5_init(md5_state_t *pms);
 
@@ -86,8 +81,4 @@ void md5_append(md5_state_t *pms, const void *data, size_t nbytes);
 /* Finish the message and return the digest. */
 void md5_finish(md5_state_t *pms, md5_byte_t digest[16]);
 
-#ifdef __cplusplus
-}  /* end extern "C" */
-#endif
-
 #endif /* MD5_INCLUDED */
diff --git a/src/os/macosx/macos.h b/src/os/macosx/macos.h
index ba33ce6028..b8a6cd5110 100644
--- a/src/os/macosx/macos.h
+++ b/src/os/macosx/macos.h
@@ -11,15 +11,9 @@
  * the function then adds text that tells the user to update and then report the bug if it's present in the newest version
  * It also quits in a nice way since we call it when we know something happened that will crash OpenTTD (like a needed pointer turns out to be NULL or similar)
  */
-#ifdef __cplusplus
-extern "C" {
-#endif //__cplusplus
-	void ShowMacDialog ( const char *title, const char *message, const char *buttonLabel );
-	void ShowMacAssertDialog ( const char *function, const char *file, const int line, const char *expression );
-	void ShowMacErrorDialog(const char *error);
-#ifdef __cplusplus
-}
-#endif //__cplusplus
+void ShowMacDialog ( const char *title, const char *message, const char *buttonLabel );
+void ShowMacAssertDialog ( const char *function, const char *file, const int line, const char *expression );
+void ShowMacErrorDialog(const char *error);
 
 // Since MacOS X users will never see an assert unless they started the game from a terminal
 // we're using a custom assert(e) macro.
diff --git a/src/os/macosx/macos.m b/src/os/macosx/macos.mm
similarity index 100%
rename from src/os/macosx/macos.m
rename to src/os/macosx/macos.mm
diff --git a/src/unix.cpp b/src/unix.cpp
index fa49eca4df..cee8082d9c 100644
--- a/src/unix.cpp
+++ b/src/unix.cpp
@@ -127,9 +127,9 @@ void ShowOSErrorBox(const char *buf)
 }
 
 #ifdef WITH_COCOA
-extern "C" void cocoaSetWorkingDirectory(void);
-extern "C" void cocoaSetupAutoreleasePool(void);
-extern "C" void cocoaReleaseAutoreleasePool(void);
+void cocoaSetWorkingDirectory(void);
+void cocoaSetupAutoreleasePool(void);
+void cocoaReleaseAutoreleasePool(void);
 #endif
 
 int CDECL main(int argc, char* argv[])
diff --git a/src/video/cocoa_v.h b/src/video/cocoa_v.h
index 42e55bccae..1512a0b649 100644
--- a/src/video/cocoa_v.h
+++ b/src/video/cocoa_v.h
@@ -5,22 +5,9 @@
 
 #include "../hal.h"
 
-#ifndef __cplusplus
-/* Really ugly workaround
- * It should be solved right as soon as possible */
-typedef uint32 SpriteID;
-#endif //__cplusplus
-
+#include "../openttd.h"
 #include "../gfx.h"
 
-#ifdef __cplusplus
-extern "C" {
-#endif //__cplusplus
-
 extern const HalVideoDriver _cocoa_video_driver;
 
-#ifdef __cplusplus
-} // extern "C"
-#endif //__cplusplus
-
 #endif
diff --git a/src/video/cocoa_v.m b/src/video/cocoa_v.mm
similarity index 96%
rename from src/video/cocoa_v.m
rename to src/video/cocoa_v.mm
index f476c905cc..aaa9475ef0 100644
--- a/src/video/cocoa_v.m
+++ b/src/video/cocoa_v.mm
@@ -13,19 +13,28 @@
 #import <sys/param.h> /* for MAXPATHLEN */
 #import <unistd.h>
 
+/**
+ * Important notice regarding all modifications!!!!!!!
+ * There are certain limitations because the file is objective C++.
+ * gdb has limitations.
+ * C++ and objective C code can't be joined in all cases (classes stuff).
+ * Read http://developer.apple.com/releasenotes/Cocoa/Objective-C++.html for more information.
+ */
+
+
 /* Portions of CPS.h */
 typedef struct CPSProcessSerNum {
 	UInt32 lo;
 	UInt32 hi;
 } CPSProcessSerNum;
 
-extern OSErr CPSGetCurrentProcess(CPSProcessSerNum* psn);
-extern OSErr CPSEnableForegroundOperation(CPSProcessSerNum* psn, UInt32 _arg2, UInt32 _arg3, UInt32 _arg4, UInt32 _arg5);
-extern OSErr CPSSetFrontProcess(CPSProcessSerNum* psn);
+extern "C" OSErr CPSGetCurrentProcess(CPSProcessSerNum* psn);
+extern "C" OSErr CPSEnableForegroundOperation(CPSProcessSerNum* psn, UInt32 _arg2, UInt32 _arg3, UInt32 _arg4, UInt32 _arg5);
+extern "C" OSErr CPSSetFrontProcess(CPSProcessSerNum* psn);
 
 /* From Menus.h (according to Xcode Developer Documentation) */
-extern void ShowMenuBar(void);
-extern void HideMenuBar(void);
+extern "C" void ShowMenuBar(void);
+extern "C" void HideMenuBar(void);
 
 /* Disables a warning. This is needed since the method exists but has been dropped from the header, supposedly as of 10.4. */
 #if (MAC_OS_X_VERSION_MAX_ALLOWED >= MAC_OS_X_VERSION_10_4)
@@ -353,7 +362,7 @@ static void QZ_DoUnsidedModifiers(unsigned int newMods)
 	const int mapping[] = { QZ_CAPSLOCK, QZ_LSHIFT, QZ_LCTRL, QZ_LALT, QZ_LMETA };
 
 	int i;
-	int bit;
+	unsigned int bit;
 
 	if (_cocoa_video_data.current_mods == newMods) return;
 
@@ -817,7 +826,7 @@ static void QZ_SetPortAlphaOpaque(void)
 	newViewFrame = [ _cocoa_video_data.qdview frame ];
 
 	/* Update the pixels and pitch */
-	thePort = [ _cocoa_video_data.qdview qdPort ];
+	thePort = (OpaqueGrafPtr*) [ _cocoa_video_data.qdview qdPort ];
 	LockPortBits(thePort);
 
 	_cocoa_video_data.realpixels = GetPixBaseAddr(GetPortPixMap(thePort));
@@ -1083,7 +1092,7 @@ static void QZ_DrawWindow(void)
 	QZ_DrawResizeIcon();
 
 	/* Flush the dirty region */
-	QDFlushPortBuffer([ _cocoa_video_data.qdview qdPort ], dirty);
+	QDFlushPortBuffer( (OpaqueGrafPtr*) [ _cocoa_video_data.qdview qdPort ], dirty);
 	DisposeRgn(dirty);
 	DisposeRgn(temp);
 
@@ -1163,10 +1172,12 @@ static const char* QZ_SetVideoWindowed(uint width, uint height)
 		[ _cocoa_video_data.window makeKeyAndOrderFront:nil ];
 	}
 
-	LockPortBits([ _cocoa_video_data.qdview qdPort ]);
-	_cocoa_video_data.realpixels = GetPixBaseAddr(GetPortPixMap([ _cocoa_video_data.qdview qdPort ]));
-	_cocoa_video_data.pitch = GetPixRowBytes(GetPortPixMap([ _cocoa_video_data.qdview qdPort ]));
-	UnlockPortBits([ _cocoa_video_data.qdview qdPort ]);
+	CGrafPtr thePort = (OpaqueGrafPtr*) [ _cocoa_video_data.qdview qdPort ];
+
+	LockPortBits(thePort);
+	_cocoa_video_data.realpixels = GetPixBaseAddr(GetPortPixMap(thePort));
+	_cocoa_video_data.pitch = GetPixRowBytes(GetPortPixMap(thePort));
+	UnlockPortBits(thePort);
 
 	/* _cocoa_video_data.realpixels now points to the window's pixels
 	 * We want it to point to the *view's* pixels
@@ -1294,17 +1305,17 @@ static const char* QZ_SetVideoFullScreen(int width, int height)
 
 	/* If the mode wasn't an exact match, check if it has the right bpp, and update width and height */
 	if (!exact_match) {
-		number = CFDictionaryGetValue (_cocoa_video_data.mode, kCGDisplayBitsPerPixel);
+		number = (const __CFNumber*) CFDictionaryGetValue(_cocoa_video_data.mode, kCGDisplayBitsPerPixel);
 		CFNumberGetValue(number, kCFNumberSInt32Type, &bpp);
 		if (bpp != 8) {
 			errstr = "Failed to find display resolution";
 			goto ERR_NO_MATCH;
 		}
 
-		number = CFDictionaryGetValue(_cocoa_video_data.mode, kCGDisplayWidth);
+		number = (const __CFNumber*)CFDictionaryGetValue(_cocoa_video_data.mode, kCGDisplayWidth);
 		CFNumberGetValue(number, kCFNumberSInt32Type, &width);
 
-		number = CFDictionaryGetValue(_cocoa_video_data.mode, kCGDisplayHeight);
+		number = (const __CFNumber*)CFDictionaryGetValue(_cocoa_video_data.mode, kCGDisplayHeight);
 		CFNumberGetValue(number, kCFNumberSInt32Type, &height);
 	}
 
@@ -1412,7 +1423,7 @@ static void QZ_WaitForVerticalBlank(void)
 	double adjustment;
 	CFNumberRef refreshRateCFNumber;
 
-	refreshRateCFNumber = CFDictionaryGetValue(_cocoa_video_data.mode, kCGDisplayRefreshRate);
+	refreshRateCFNumber = (const __CFNumber*)CFDictionaryGetValue(_cocoa_video_data.mode, kCGDisplayRefreshRate);
 	if (refreshRateCFNumber == NULL) return;
 
 	if (CFNumberGetValue(refreshRateCFNumber, kCFNumberDoubleType, &refreshRate) == 0)
@@ -1487,17 +1498,17 @@ static int QZ_ListFullscreenModes(OTTDPoint* mode_list, int max_modes)
 		bool hasMode;
 		uint16 width, height;
 
-		onemode = CFArrayGetValueAtIndex(_cocoa_video_data.mode_list, i);
-		number = CFDictionaryGetValue(onemode, kCGDisplayBitsPerPixel);
+		onemode = (const __CFDictionary*)CFArrayGetValueAtIndex(_cocoa_video_data.mode_list, i);
+		number = (const __CFNumber*)CFDictionaryGetValue(onemode, kCGDisplayBitsPerPixel);
 		CFNumberGetValue (number, kCFNumberSInt32Type, &bpp);
 
 		if (bpp != 8) continue;
 
-		number = CFDictionaryGetValue(onemode, kCGDisplayWidth);
+		number = (const __CFNumber*)CFDictionaryGetValue(onemode, kCGDisplayWidth);
 		CFNumberGetValue(number, kCFNumberSInt32Type, &intvalue);
 		width = (uint16)intvalue;
 
-		number = CFDictionaryGetValue(onemode, kCGDisplayHeight);
+		number = (const __CFNumber*)CFDictionaryGetValue(onemode, kCGDisplayHeight);
 		CFNumberGetValue(number, kCFNumberSInt32Type, &intvalue);
 		height = (uint16)intvalue;
 
@@ -1713,17 +1724,17 @@ static void QZ_VideoInit(void)
 	/* Gather some information that is useful to know about the display */
 	/* Maybe this should be moved to QZ_SetVideoMode, in case this is changed after startup */
 	CFNumberGetValue(
-		CFDictionaryGetValue(_cocoa_video_data.save_mode, kCGDisplayBitsPerPixel),
+		(const __CFNumber*)CFDictionaryGetValue(_cocoa_video_data.save_mode, kCGDisplayBitsPerPixel),
 		kCFNumberSInt32Type, &_cocoa_video_data.device_bpp
 	);
 
 	CFNumberGetValue(
-		CFDictionaryGetValue(_cocoa_video_data.save_mode, kCGDisplayWidth),
+		(const __CFNumber*)CFDictionaryGetValue(_cocoa_video_data.save_mode, kCGDisplayWidth),
 		kCFNumberSInt32Type, &_cocoa_video_data.device_width
 	);
 
 	CFNumberGetValue(
-		CFDictionaryGetValue(_cocoa_video_data.save_mode, kCGDisplayHeight),
+		(const __CFNumber*)CFDictionaryGetValue(_cocoa_video_data.save_mode, kCGDisplayHeight),
 		kCFNumberSInt32Type, &_cocoa_video_data.device_height
 	);