Disable "The key you just pressed is not recognized by SDL." message by default

src/video/cocoa/SDL_cocoakeyboard.m

@@ -558,9 +558,9 @@ Cocoa_HandleKeyEvent(_THIS, NSEvent *event)
         }
 
         SDL_SendKeyboardKey(SDL_PRESSED, code);
-#if 1
+#ifdef DEBUG_SCANCODES
         if (code == SDL_SCANCODE_UNKNOWN) {
-            fprintf(stderr, "The key you just pressed is not recognized by SDL. To help get this fixed, report this to the SDL forums/mailing list <https://discourse.libsdl.org/> or to Christian Walther <cwalther@gmx.ch>. Mac virtual key code is %d.\n", scancode);
+            SDL_Log("The key you just pressed is not recognized by SDL. To help get this fixed, report this to the SDL forums/mailing list <https://discourse.libsdl.org/> or to Christian Walther <cwalther@gmx.ch>. Mac virtual key code is %d.\n", scancode);
         }
 #endif
         if (SDL_EventState(SDL_TEXTINPUT, SDL_QUERY)) {

src/video/nacl/SDL_naclevents.c

@@ -313,9 +313,11 @@ SDL_NACL_translate_keycode(int keycode)
     if (keycode < SDL_arraysize(NACL_Keycodes)) {
         scancode = NACL_Keycodes[keycode];
     }
+#ifdef DEBUG_SCANCODES
     if (scancode == SDL_SCANCODE_UNKNOWN) {
         SDL_Log("The key you just pressed is not recognized by SDL. To help get this fixed, please report this to the SDL forums/mailing list <https://discourse.libsdl.org/> NACL KeyCode %d", keycode);
     }
+#endif
     return scancode;
 }
 

src/video/riscos/SDL_riscosevents.c

@@ -40,9 +40,11 @@ SDL_RISCOS_translate_keycode(int keycode)
     if (keycode < SDL_arraysize(riscos_scancode_table)) {
         scancode = riscos_scancode_table[keycode];
 
+#ifdef DEBUG_SCANCODES
         if (scancode == SDL_SCANCODE_UNKNOWN) {
             SDL_Log("The key you just pressed is not recognized by SDL: %d", keycode);
         }
+#endif
     }
 
     return scancode;