Fix SDL.h includes

See comment in FindSDL2.cmake:
 Note that the header path has changed from SDL2/SDL.h to just SDL.h
 This needed to change because "proper" SDL convention
 is #include "SDL.h", not <SDL2/SDL.h>. This is done for portability
 reasons because not all systems place things in SDL2/ (see FreeBSD).

src/common/SoundSDL.h

@@ -21,7 +21,7 @@
 #include "RingBuffer.h"
 #include "SoundDriver.h"
 
-#include <SDL.h>
+#include "SDL.h"
 
 class SoundSDL : public SoundDriver
 {

src/gtk/window.cpp

@@ -28,7 +28,7 @@
 
 #include <sys/stat.h>
 
-#include <SDL.h>
+#include "SDL.h"
 
 #include "../Util.h"
 #include "../common/ConfigManager.h"

src/gtk/windowcallbacks.cpp

@@ -30,7 +30,7 @@
 #include <gtkmm/messagedialog.h>
 #include <gtkmm/stock.h>
 
-#include <SDL.h>
+#include "SDL.h"
 
 #include "../Util.h"
 #include "../common/ConfigManager.h"

src/sdl/SDL.cpp

@@ -43,7 +43,7 @@
 #include "../AutoBuild.h"
 #include "../version.h"
 
-#include <SDL.h>
+#include "SDL.h"
 
 #include "../Util.h"
 #include "../common/ConfigManager.h"

src/sdl/inputSDL.h

@@ -18,7 +18,7 @@
 #ifndef VBAM_SDL_INPUT_H
 #define VBAM_SDL_INPUT_H
 
-#include <SDL.h>
+#include "SDL.h"
 
 enum EKey {
     KEY_LEFT,

src/wx/sys.cpp

@@ -1,7 +1,7 @@
 #include "../common/ConfigManager.h"
 #include "../common/SoundSDL.h"
 #include "wxvbam.h"
-#include <SDL.h>
+#include "SDL.h"
 #include <wx/ffile.h>
 #include <wx/generic/prntdlgg.h>
 #include <wx/print.h>

src/wx/widgets/sdljoy.cpp

@@ -1,5 +1,5 @@
 #include "wx/sdljoy.h"
-#include <SDL.h>
+#include "SDL.h"
 #include <SDL_joystick.h>
 #include <wx/window.h>