core: Library cleanup (#1631)

* core: Split error codes into separate files

* Reduces build times and is cleaner

* core: Bring structs and enums to codebase style

* core: More style changes

src/core/cpu_patches.h

@@ -3,6 +3,8 @@
 
 #pragma once
 
+#include "common/types.h"
+
 namespace Core {
 
 /// Initializes a stack for the current thread for use by patch implementations.