SDL: main: Emscripten needs SDL_main_impl.h now that it has its own SDL_RunApp.

SDL Commits
1 
From eb212ac4edcc331b8215dc706abca95af2d51d87 Mon Sep 17 00:00:00 2001
From: "Ryan C. Gordon" <[EMAIL REDACTED]>
Date: Sun, 18 Aug 2024 23:53:13 -0400
Subject: [PATCH] main: Emscripten needs SDL_main_impl.h now that it has its
 own SDL_RunApp.

Reference PR #10171.
---
 include/SDL3/SDL_main.h | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/include/SDL3/SDL_main.h b/include/SDL3/SDL_main.h
index b3cb8e2cd79ec..8b89e880714ad 100644
--- a/include/SDL3/SDL_main.h
+++ b/include/SDL3/SDL_main.h
@@ -584,7 +584,8 @@ extern SDL_DECLSPEC void SDLCALL SDL_GDKSuspendComplete(void);
     /* include header-only SDL_main implementations */
     #if defined(SDL_MAIN_USE_CALLBACKS) \
         || defined(SDL_PLATFORM_WIN32) || defined(SDL_PLATFORM_GDK) || defined(SDL_PLATFORM_IOS) || defined(SDL_PLATFORM_TVOS) \
-        || defined(SDL_PLATFORM_3DS) || defined(SDL_PLATFORM_NGAGE) || defined(SDL_PLATFORM_PS2) || defined(SDL_PLATFORM_PSP)
+        || defined(SDL_PLATFORM_3DS) || defined(SDL_PLATFORM_NGAGE) || defined(SDL_PLATFORM_PS2) || defined(SDL_PLATFORM_PSP) \
+        || defined(SDL_PLATFORM_EMSCRIPTEN)
 
         /* platforms which main (-equivalent) can be implemented in plain C */
         #include <SDL3/SDL_main_impl.h>