SDL: SDL_thread.c: fix unused function SDL_FreeErrBuf when building without thread support (emscripten)

SDL Commits
#1 
From 2105c7f6edde487d5e2281d1c4efede963490d96 Mon Sep 17 00:00:00 2001
From: Anonymous Maarten <[EMAIL REDACTED]>
Date: Thu, 6 Oct 2022 00:58:26 +0200
Subject: [PATCH] SDL_thread.c: fix unused function SDL_FreeErrBuf when
 building without thread support (emscripten)

---
 src/thread/SDL_thread.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/src/thread/SDL_thread.c b/src/thread/SDL_thread.c
index 65610339c40b..4e51be68babd 100644
--- a/src/thread/SDL_thread.c
+++ b/src/thread/SDL_thread.c
@@ -211,6 +211,7 @@ SDL_GetStaticErrBuf()
     return &SDL_global_error;
 }
 
+#if !SDL_THREADS_DISABLED
 static void SDLCALL
 SDL_FreeErrBuf(void *data)
 {
@@ -221,6 +222,7 @@ SDL_FreeErrBuf(void *data)
     }
     errbuf->free_func(errbuf);
 }
+#endif
 
 /* Routine to get the thread-specific error variable */
 SDL_error *