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/core/SDL_core_unsupported.c

@@ -97,7 +97,7 @@ void SDL_UnregisterApp(void)
 
 /* Returns SDL_WinRT_DeviceFamily enum */
 SDL_DECLSPEC int SDLCALL SDL_GetWinRTDeviceFamily(void);
-int SDL_GetWinRTDeviceFamily()
+int SDL_GetWinRTDeviceFamily(void)
 {
     SDL_Unsupported();
     return 0; /* SDL_WINRT_DEVICEFAMILY_UNKNOWN */
@@ -115,20 +115,20 @@ const char *SDL_GetWinRTFSPath(int pathType)
 #ifndef SDL_PLATFORM_ANDROID
 
 SDL_DECLSPEC void SDLCALL SDL_SendAndroidBackButton(void);
-void SDL_SendAndroidBackButton()
+void SDL_SendAndroidBackButton(void)
 {
     SDL_Unsupported();
 }
 
 SDL_DECLSPEC void *SDLCALL SDL_GetAndroidActivity(void);
-void *SDL_GetAndroidActivity()
+void *SDL_GetAndroidActivity(void)
 {
     SDL_Unsupported();
     return NULL;
 }
 
 SDL_DECLSPEC const char *SDLCALL SDL_GetAndroidCachePath(void);
-const char* SDL_GetAndroidCachePath()
+const char* SDL_GetAndroidCachePath(void)
 {
     SDL_Unsupported();
     return NULL;
@@ -136,7 +136,7 @@ const char* SDL_GetAndroidCachePath()
 
 
 SDL_DECLSPEC const char *SDLCALL SDL_GetAndroidExternalStoragePath(void);
-const char* SDL_GetAndroidExternalStoragePath()
+const char* SDL_GetAndroidExternalStoragePath(void)
 {
     SDL_Unsupported();
     return NULL;
@@ -156,7 +156,7 @@ const char *SDL_GetAndroidInternalStoragePath(void)
 }
 
 SDL_DECLSPEC void *SDLCALL SDL_GetAndroidJNIEnv(void);
-void *SDL_GetAndroidJNIEnv()
+void *SDL_GetAndroidJNIEnv(void)
 {
     SDL_Unsupported();
     return NULL;
@@ -192,20 +192,20 @@ int SDL_ShowAndroidToast(const char* message, int duration, int gravity, int xof
 }
 
 SDL_DECLSPEC int SDLCALL SDL_GetAndroidSDKVersion(void);
-int SDL_GetAndroidSDKVersion()
+int SDL_GetAndroidSDKVersion(void)
 {
     return SDL_Unsupported();
 }
 
 SDL_DECLSPEC SDL_bool SDLCALL SDL_IsAndroidTV(void);
-SDL_bool SDL_IsAndroidTV()
+SDL_bool SDL_IsAndroidTV(void)
 {
     SDL_Unsupported();
     return SDL_FALSE;
 }
 
 SDL_DECLSPEC SDL_bool SDLCALL SDL_IsChromebook(void);
-SDL_bool SDL_IsChromebook()
+SDL_bool SDL_IsChromebook(void)
 {
     SDL_Unsupported();
     return SDL_FALSE;

src/core/android/SDL_android.c

@@ -898,18 +898,18 @@ JNIEXPORT void JNICALL SDL_JAVA_INTERFACE(onNativeDropFile)(
 }
 
 /* Lock / Unlock Mutex */
-void Android_ActivityMutex_Lock()
+void Android_ActivityMutex_Lock(void)
 {
     SDL_LockMutex(Android_ActivityMutex);
 }
 
-void Android_ActivityMutex_Unlock()
+void Android_ActivityMutex_Unlock(void)
 {
     SDL_UnlockMutex(Android_ActivityMutex);
 }
 
 /* Lock the Mutex when the Activity is in its 'Running' state */
-void Android_ActivityMutex_Lock_Running()
+void Android_ActivityMutex_Lock_Running(void)
 {
     int pauseSignaled = 0;
     int resumeSignaled = 0;
@@ -1561,13 +1561,13 @@ void Android_JNI_SetOrientation(int w, int h, int resizable, const char *hint)
     (*env)->DeleteLocalRef(env, jhint);
 }
 
-void Android_JNI_MinizeWindow()
+void Android_JNI_MinizeWindow(void)
 {
     JNIEnv *env = Android_JNI_GetEnv();
     (*env)->CallStaticVoidMethod(env, mActivityClass, midMinimizeWindow);
 }
 
-SDL_bool Android_JNI_ShouldMinimizeOnFocusLoss()
+SDL_bool Android_JNI_ShouldMinimizeOnFocusLoss(void)
 {
     JNIEnv *env = Android_JNI_GetEnv();
     return (*env)->CallStaticBooleanMethod(env, mActivityClass, midShouldMinimizeOnFocusLoss);
@@ -1947,7 +1947,7 @@ static SDL_bool Android_JNI_ExceptionOccurred(SDL_bool silent)
     return SDL_FALSE;
 }
 
-static void Internal_Android_Create_AssetManager()
+static void Internal_Android_Create_AssetManager(void)
 {
 
     struct LocalReferenceHolder refs = LocalReferenceHolder_Setup(__FUNCTION__);
@@ -1986,7 +1986,7 @@ static void Internal_Android_Create_AssetManager()
     LocalReferenceHolder_Cleanup(&refs);
 }
 
-static void Internal_Android_Destroy_AssetManager()
+static void Internal_Android_Destroy_AssetManager(void)
 {
     JNIEnv *env = Android_JNI_GetEnv();
 
@@ -2206,7 +2206,7 @@ int Android_JNI_GetPowerInfo(int *plugged, int *charged, int *battery, int *seco
 }
 
 /* Add all touch devices */
-void Android_JNI_InitTouch()
+void Android_JNI_InitTouch(void)
 {
     JNIEnv *env = Android_JNI_GetEnv();
     (*env)->CallStaticVoidMethod(env, mActivityClass, midInitTouch);

src/core/freebsd/SDL_evdev_kbd_freebsd.c

@@ -133,7 +133,7 @@ static void kbd_cleanup_signal_action(int signum, siginfo_t *info, void *ucontex
     SDL_EVDEV_kbd_reraise_signal(signum);
 }
 
-static void kbd_unregister_emerg_cleanup()
+static void kbd_unregister_emerg_cleanup(void)
 {
     int tabidx;
 

src/core/openbsd/SDL_wscons_kbd.c

@@ -452,7 +452,7 @@ static SDL_WSCONS_input_data *SDL_WSCONS_Init_Keyboard(const char *dev)
     return input;
 }
 
-void SDL_WSCONS_Init()
+void SDL_WSCONS_Init(void)
 {
     inputs[0] = SDL_WSCONS_Init_Keyboard("/dev/wskbd0");
     inputs[1] = SDL_WSCONS_Init_Keyboard("/dev/wskbd1");
@@ -463,7 +463,7 @@ void SDL_WSCONS_Init()
     return;
 }
 
-void SDL_WSCONS_Quit()
+void SDL_WSCONS_Quit(void)
 {
     int i = 0;
     SDL_WSCONS_input_data *input = NULL;
@@ -924,7 +924,7 @@ static void updateKeyboard(SDL_WSCONS_input_data *input)
     }
 }
 
-void SDL_WSCONS_PumpEvents()
+void SDL_WSCONS_PumpEvents(void)
 {
     int i = 0;
     for (i = 0; i < 4; i++) {

src/core/openbsd/SDL_wscons_mouse.c

@@ -35,7 +35,7 @@ typedef struct SDL_WSCONS_mouse_input_data
     SDL_MouseID mouseID;
 } SDL_WSCONS_mouse_input_data;
 
-SDL_WSCONS_mouse_input_data *SDL_WSCONS_Init_Mouse()
+SDL_WSCONS_mouse_input_data *SDL_WSCONS_Init_Mouse(void)
 {
 #ifdef WSMOUSEIO_SETVERSION
     int version = WSMOUSE_EVENT_VERSION;

src/core/unix/SDL_appid.c

@@ -24,7 +24,7 @@
 #include "SDL_appid.h"
 #include <unistd.h>
 
-const char *SDL_GetExeName()
+const char *SDL_GetExeName(void)
 {
     static const char *proc_name = NULL;
 
@@ -57,7 +57,7 @@ const char *SDL_GetExeName()
     return proc_name;
 }
 
-const char *SDL_GetAppID()
+const char *SDL_GetAppID(void)
 {
     /* Always check the hint, as it may have changed */
     const char *id_str = SDL_GetHint(SDL_HINT_APP_ID);