Utils: Add retrocompatability header

QRunnable::create was added in Qt 5.15, but Ubuntu still uses 5.12.
This reimplements that functionality until Ubuntu moves to >= 5.15

src/utils/Compat.cpp

@@ -0,0 +1,16 @@
+#include "Compat.h"
+
+Utils::Compat::StdFunctionRunnable::StdFunctionRunnable(std::function<void()> func) :
+	cb(std::move(func))
+{
+}
+
+void Utils::Compat::StdFunctionRunnable::run()
+{
+	cb();
+}
+
+QRunnable *Utils::Compat::CreateFunctionRunnable(std::function<void()> func)
+{
+	return new Utils::Compat::StdFunctionRunnable(std::move(func));
+}

src/utils/Compat.h

@@ -0,0 +1,18 @@
+#pragma once
+
+#include <functional>
+#include <QRunnable>
+
+namespace Utils {
+	namespace Compat {
+		// Reimplement QRunnable for std::function. Retrocompatability for Qt < 5.15
+		class StdFunctionRunnable : public QRunnable {
+			std::function<void()> cb;
+			public:
+				StdFunctionRunnable(std::function<void()> func);
+				void run() override;
+		};
+
+		QRunnable *CreateFunctionRunnable(std::function<void()> func);
+	}
+}

src/utils/Utils.h

@@ -4,3 +4,4 @@
 #include "Json.h"
 #include "Obs.h"
 #include "Platform.h"
+#include "Compat.h"