Fixed bug 3517 - Compiler warnings with gcc -Wstrict-prototypes

felix

Compiling even a simple SDL2 'hello world' program with gcc -Wstrict-prototypes (GCC 6.2.1) results in warnings like:

/usr/include/SDL2/SDL_gamecontroller.h:143:1: attention : function declaration isn't a prototype [-Wstrict-prototypes]
 extern DECLSPEC int SDLCALL SDL_GameControllerNumMappings();
 ^~~~~~

It seems there is a missing 'void' between the parentheses.

Xcode-iOS/Demos/src/common.c

@@ -39,7 +39,7 @@ fatalError(const char *string)
 static Uint64 prevTime = 0;
 
 double
-updateDeltaTime()
+updateDeltaTime(void)
 {
     Uint64 curTime;
     double deltaTime;