Fix warning for Android NDK compiler: "function declaration without a prototype is deprecated in all versions of C [-Wstrict-prototypes]"

https://stackoverflow.com/questions/42125/warning-error-function-declaration-isnt-a-prototype
In C int foo() and int foo(void) are different functions. int foo() accepts an arbitrary number of arguments, while int foo(void) accepts 0 arguments. In C++ they mean the same thing.

src/video/SDL_blit.c

@@ -103,7 +103,7 @@ static int SDLCALL SDL_SoftBlit(SDL_Surface *src, SDL_Rect *srcrect,
 #ifdef __MACOSX__
 #include <sys/sysctl.h>
 
-static SDL_bool SDL_UseAltivecPrefetch()
+static SDL_bool SDL_UseAltivecPrefetch(void)
 {
     const char key[] = "hw.l3cachesize";
     u_int64_t result = 0;

src/video/SDL_stretch.c

@@ -367,7 +367,7 @@ static void printf_128(const char *str, __m128i var)
 }
 #endif
 
-static SDL_INLINE int hasSSE2()
+static SDL_INLINE int hasSSE2(void)
 {
     static int val = -1;
     if (val != -1) {

src/video/android/SDL_androidmouse.c

@@ -78,7 +78,7 @@ static SDL_Cursor *Android_WrapCursor(int custom_cursor, int system_cursor)
     return cursor;
 }
 
-static SDL_Cursor *Android_CreateDefaultCursor()
+static SDL_Cursor *Android_CreateDefaultCursor(void)
 {
     return Android_WrapCursor(0, SDL_SYSTEM_CURSOR_ARROW);
 }
@@ -116,7 +116,7 @@ static void Android_FreeCursor(SDL_Cursor *cursor)
     SDL_free(cursor);
 }
 
-static SDL_Cursor *Android_CreateEmptyCursor()
+static SDL_Cursor *Android_CreateEmptyCursor(void)
 {
     if (!empty_cursor) {
         SDL_Surface *empty_surface = SDL_CreateRGBSurfaceWithFormat(0, 1, 1, 32, SDL_PIXELFORMAT_ARGB8888);
@@ -129,7 +129,7 @@ static SDL_Cursor *Android_CreateEmptyCursor()
     return empty_cursor;
 }
 
-static void Android_DestroyEmptyCursor()
+static void Android_DestroyEmptyCursor(void)
 {
     if (empty_cursor) {
         Android_FreeCursor(empty_cursor);

src/video/directfb/SDL_DirectFB_render.c

@@ -561,7 +561,7 @@ static void DirectFB_UnlockTexture(SDL_Renderer * renderer, SDL_Texture * textur
     }
 }
 
-static void DirectFB_SetTextureScaleMode()
+static void DirectFB_SetTextureScaleMode(void)
 {
 }
 

src/video/dummy/SDL_nullvideo.c

@@ -131,7 +131,7 @@ VideoBootStrap DUMMY_evdev_bootstrap = {
     NULL /* no ShowMessageBox implementation */
 };
 void SDL_EVDEV_Init(void);
-void SDL_EVDEV_Poll();
+void SDL_EVDEV_Poll(void);
 void SDL_EVDEV_Quit(void);
 static void DUMMY_EVDEV_Poll(_THIS)
 {

src/video/emscripten/SDL_emscriptenmouse.c

@@ -222,7 +222,7 @@ static int Emscripten_SetRelativeMouseMode(SDL_bool enabled)
     return -1;
 }
 
-void Emscripten_InitMouse()
+void Emscripten_InitMouse(void)
 {
     SDL_Mouse *mouse = SDL_GetMouse();
 
@@ -236,7 +236,7 @@ void Emscripten_InitMouse()
     SDL_SetDefaultCursor(Emscripten_CreateDefaultCursor());
 }
 
-void Emscripten_FiniMouse()
+void Emscripten_FiniMouse(void)
 {
 }
 

src/video/n3ds/SDL_n3dsswkb.c

@@ -30,17 +30,17 @@
 static SwkbdState sw_keyboard;
 const static size_t BUFFER_SIZE = 256;
 
-void N3DS_SwkbInit()
+void N3DS_SwkbInit(void)
 {
     swkbdInit(&sw_keyboard, SWKBD_TYPE_NORMAL, 2, -1);
 }
 
-void N3DS_SwkbPoll()
+void N3DS_SwkbPoll(void)
 {
     return;
 }
 
-void N3DS_SwkbQuit()
+void N3DS_SwkbQuit(void)
 {
     return;
 }

src/video/raspberry/SDL_rpivideo.c

@@ -56,7 +56,7 @@ static void RPI_Destroy(SDL_VideoDevice *device)
     SDL_free(device);
 }
 
-static int RPI_GetRefreshRate()
+static int RPI_GetRefreshRate(void)
 {
     TV_DISPLAY_STATE_T tvstate;
     if (vc_tv_get_display_state(&tvstate) == 0) {

src/video/wayland/SDL_waylandvideo.c

@@ -79,7 +79,7 @@ static void Wayland_VideoQuit(_THIS);
 
 /* Find out what class name we should use
  * Based on src/video/x11/SDL_x11video.c */
-static char *get_classname()
+static char *get_classname(void)
 {
     /* !!! FIXME: this is probably wrong, albeit harmless in many common cases. From protocol spec:
         "The surface class identifies the general class of applications

src/video/windows/SDL_windowsevents.c

@@ -330,7 +330,7 @@ static SDL_Scancode WindowsScanCodeToSDLScanCode(LPARAM lParam, WPARAM wParam)
 }
 
 #if !defined(__XBOXONE__) && !defined(__XBOXSERIES__)
-static SDL_bool WIN_ShouldIgnoreFocusClick()
+static SDL_bool WIN_ShouldIgnoreFocusClick(void)
 {
     return !SDL_GetHintBoolean(SDL_HINT_MOUSE_FOCUS_CLICKTHROUGH, SDL_FALSE);
 }
@@ -1797,7 +1797,7 @@ WIN_WindowProc(HWND hwnd, UINT msg, WPARAM wParam, LPARAM lParam)
 }
 
 #if !defined(__XBOXONE__) && !defined(__XBOXSERIES__)
-static void WIN_UpdateClipCursorForWindows()
+static void WIN_UpdateClipCursorForWindows(void)
 {
     SDL_VideoDevice *_this = SDL_GetVideoDevice();
     SDL_Window *window;
@@ -1819,7 +1819,7 @@ static void WIN_UpdateClipCursorForWindows()
     }
 }
 
-static void WIN_UpdateMouseCapture()
+static void WIN_UpdateMouseCapture(void)
 {
     SDL_Window *focusWindow = SDL_GetKeyboardFocus();
 
@@ -2093,7 +2093,7 @@ int SDL_RegisterApp(const char *name, Uint32 style, void *hInst)
 }
 
 /* Unregisters the windowclass registered in SDL_RegisterApp above. */
-void SDL_UnregisterApp()
+void SDL_UnregisterApp(void)
 {
     WNDCLASSEX wcex;
 

src/video/windows/SDL_windowskeyboard.c

@@ -166,7 +166,7 @@ void WIN_QuitKeyboard(_THIS)
 #endif /* !SDL_DISABLE_WINDOWS_IME */
 }
 
-void WIN_ResetDeadKeys()
+void WIN_ResetDeadKeys(void)
 {
     /*
     if a deadkey has been typed, but not the next character (which the deadkey might modify),
@@ -367,7 +367,7 @@ static void UILess_ReleaseSinks(SDL_VideoData *videodata);
 static void UILess_EnableUIUpdates(SDL_VideoData *videodata);
 static void UILess_DisableUIUpdates(SDL_VideoData *videodata);
 
-static SDL_bool WIN_ShouldShowNativeUI()
+static SDL_bool WIN_ShouldShowNativeUI(void)
 {
     return SDL_GetHintBoolean(SDL_HINT_IME_SHOW_UI, SDL_FALSE);
 }

src/video/windows/SDL_windowsmouse.c

@@ -474,7 +474,7 @@ static void WIN_SetLinearMouseScale(int mouse_speed)
     }
 }
 
-void WIN_UpdateMouseSystemScale()
+void WIN_UpdateMouseSystemScale(void)
 {
     int mouse_speed;
     int params[3] = { 0, 0, 0 };

src/video/x11/SDL_x11video.c

@@ -50,7 +50,7 @@ static int X11_VideoInit(_THIS);
 static void X11_VideoQuit(_THIS);
 
 /* Find out what class name we should use */
-static char *get_classname()
+static char *get_classname(void)
 {
     char *spot;
 #if defined(__LINUX__) || defined(__FREEBSD__)

src/video/x11/SDL_x11xfixes.c

@@ -74,12 +74,12 @@ void X11_InitXfixes(_THIS)
     xfixes_initialized = 1;
 }
 
-int X11_XfixesIsInitialized()
+int X11_XfixesIsInitialized(void)
 {
     return xfixes_initialized;
 }
 
-int X11_GetXFixesSelectionNotifyEvent()
+int X11_GetXFixesSelectionNotifyEvent(void)
 {
     return xfixes_selection_notify_event;
 }

src/video/x11/SDL_x11xinput2.c

@@ -453,7 +453,7 @@ void X11_Xinput2SelectTouch(_THIS, SDL_Window *window)
 #endif
 }
 
-int X11_Xinput2IsInitialized()
+int X11_Xinput2IsInitialized(void)
 {
 #ifdef SDL_VIDEO_DRIVER_X11_XINPUT2
     return xinput2_initialized;
@@ -462,7 +462,7 @@ int X11_Xinput2IsInitialized()
 #endif
 }
 
-int X11_Xinput2IsMultitouchSupported()
+int X11_Xinput2IsMultitouchSupported(void)
 {
 #ifdef SDL_VIDEO_DRIVER_X11_XINPUT2_SUPPORTS_MULTITOUCH
     return xinput2_initialized && xinput2_multitouch_supported;