3DS: Support simple message boxes

src/SDL_assert.c

@@ -283,7 +283,7 @@ static SDL_AssertState SDLCALL SDL_PromptAssertion(const SDL_AssertData *data, v
                 break;
             }
         }
-#elif defined(HAVE_STDIO_H)
+#elif defined(HAVE_STDIO_H) && !defined(SDL_PLATFORM_3DS)
         // this is a little hacky.
         for (;;) {
             char buf[32];
@@ -310,6 +310,8 @@ static SDL_AssertState SDLCALL SDL_PromptAssertion(const SDL_AssertData *data, v
                 break;
             }
         }
+#else
+        SDL_ShowSimpleMessageBox(SDL_MESSAGEBOX_WARNING, "Assertion Failed", message, window);
 #endif // HAVE_STDIO_H
     }
 

src/video/SDL_video.c

@@ -59,6 +59,10 @@
 #include <emscripten.h>
 #endif
 
+#ifdef SDL_PLATFORM_3DS
+#include <3ds.h>
+#endif
+
 #ifdef SDL_PLATFORM_LINUX
 #include <sys/types.h>
 #include <sys/stat.h>
@@ -5518,6 +5522,23 @@ bool SDL_ShowSimpleMessageBox(SDL_MessageBoxFlags flags, const char *title, cons
     },
             title, message);
     return true;
+#elif defined(SDL_PLATFORM_3DS)
+    errorConf errCnf;
+    bool hasGpuRight;
+
+    // If the video subsystem has not been initialised, set up graphics temporarily
+    hasGpuRight = gspHasGpuRight();
+    if (!hasGpuRight)
+        gfxInitDefault();
+
+    errorInit(&errCnf, ERROR_TEXT_WORD_WRAP, CFG_LANGUAGE_EN);
+    errorText(&errCnf, message);
+    errorDisp(&errCnf);
+
+    if (!hasGpuRight)
+        gfxExit();
+
+    return true;
 #else
     SDL_MessageBoxData data;
     SDL_MessageBoxButtonData button;