virtual joysticks: MSVC support part 1/2, make driver's .c file be uniquely named

src/joystick/SDL_joystick.c

@@ -47,7 +47,7 @@
 #endif
 
 #if SDL_JOYSTICK_VIRTUAL
-#include "./virtual/SDL_sysjoystick_c.h"
+#include "./virtual/SDL_virtualjoystick_c.h"
 #endif
 
 static SDL_JoystickDriver *SDL_joystick_drivers[] = {

src/joystick/virtual/SDL_virtualjoystick.c

@@ -24,7 +24,7 @@
 
 /* This is the virtual implementation of the SDL joystick API */
 
-#include "SDL_sysjoystick_c.h"
+#include "SDL_virtualjoystick_c.h"
 #include "../SDL_sysjoystick.h"
 #include "../SDL_joystick_c.h"
 

src/joystick/virtual/SDL_virtualjoystick_c.h

@@ -20,8 +20,8 @@
 */
 #include "../../SDL_internal.h"
 
-#ifndef SDL_JOYSTICK_VIRTUAL_H
-#define SDL_JOYSTICK_VIRTUAL_H
+#ifndef SDL_VIRTUALJOYSTICK_C_H
+#define SDL_VIRTUALJOYSTICK_C_H
 
 #if SDL_JOYSTICK_VIRTUAL
 
@@ -59,4 +59,4 @@ int SDL_JoystickSetVirtualButtonInner(SDL_Joystick * joystick, int button, Uint8
 int SDL_JoystickSetVirtualHatInner(SDL_Joystick * joystick, int hat, Uint8 value);
 
 #endif  /* SDL_JOYSTICK_VIRTUAL */
-#endif  /* SDL_JOYSTICK_VIRTUAL_H */
+#endif  /* SDL_VIRTUALJOYSTICK_C_H */