iOS: Fix hang when task switching in GL mode

Common/GPU/OpenGL/GLRenderManager.cpp

@@ -183,6 +183,16 @@ void GLRenderManager::StopThread() {
 	}
 }
 
+void GLRenderManager::StartThread() {
+	// There's not really a lot to do here anymore.
+	INFO_LOG(G3D, "GLRenderManager::StartThread()");
+	if (!runCompileThread_) {
+		runCompileThread_ = true;
+	} else {
+		INFO_LOG(G3D, "GL submission thread was already running.");
+	}
+}
+
 std::string GLRenderManager::GetGpuProfileString() const {
 	int curFrame = curFrame_;
 	const GLQueueProfileContext &profile = frameData_[curFrame].profile;

Common/GPU/OpenGL/GLRenderManager.h

@@ -834,6 +834,7 @@ public:
 		}
 	}
 
+	void StartThread();  // Currently only used on iOS, since we fully recreate the context on Android
 	void StopThread();
 
 	bool SawOutOfMemory() {
@@ -873,6 +874,7 @@ private:
 	FastVec<GLRInitStep> initSteps_;
 
 	// Execution time state
+	// TODO: Rename this, as we don't actually use a compile thread on OpenGL.
 	bool runCompileThread_ = true;
 
 	// Thread is managed elsewhere, and should call ThreadFrame.