Disable texture decode thread if shared context are not available (SDL1).

indra/llrender/llimagegl.cpp

@@ -2434,6 +2434,16 @@ LLImageGLThread::LLImageGLThread(LLWindow* window)
     mFinished = false;
 
     mContext = mWindow->createSharedContext();
+	
+	// <FS:ND> If context creating is not supported (SDL1), mark texture thread disabled and exit
+	if( !mContext )
+	{
+		sEnabled = false;
+		mFinished = true;
+		return;
+	}
+	// </FS:ND>
+	
     ThreadPool::start();
 }
 

indra/llwindow/llwindowsdl.cpp

@@ -3024,8 +3024,6 @@ std::vector<std::string> LLWindowSDL::getDynamicFallbackFontList()
 	return rtns;
 }
 
-#pragma GCC error "Unimplemented. Either disable threaded texture decoding, implent those methods or switch to SDL2."
-
 void* LLWindowSDL::createSharedContext()
 {
   LL_WARNS() << "Not available" << LL_ENDL;