Prepare event manager

The event manager forms the basis for semantic logging.
The emulator transmits events and the manager can handle them.
This means to either print information to stdout, do nothing, etc...

src/windows-emulator/generic_logger.hpp

@@ -0,0 +1,28 @@
+#pragma once
+#include <utils/object.hpp>
+
+#if defined(__clang__) || defined(__GNUC__)
+#define FORMAT_ATTRIBUTE(fmt_pos, var_pos) __attribute__((format(printf, fmt_pos, var_pos)))
+#else
+#define FORMAT_ATTRIBUTE(fmt_pos, var_pos)
+#endif
+
+enum class color
+{
+    black,
+    red,
+    green,
+    yellow,
+    blue,
+    cyan,
+    pink,
+    white,
+    gray,
+    dark_gray,
+};
+
+struct generic_logger : utils::object
+{
+    virtual void print(color c, std::string_view message) = 0;
+    virtual void print(color c, const char* message, ...) FORMAT_ATTRIBUTE(3, 4) = 0;
+};