Fix some includes in source/lib

Make include-what-you-use happy with some files in source/lib and fix
what needs to be fixed.

Ref: #8086
Signed-off-by: Ralph Sennhauser <ralph.sennhauser@gmail.com>

source/lib/bits.cpp

@@ -1,4 +1,4 @@
-/* Copyright (C) 2020 Wildfire Games.
+/* Copyright (C) 2025 Wildfire Games.
  *
  * Permission is hereby granted, free of charge, to any person obtaining
  * a copy of this software and associated documentation files (the
@@ -25,7 +25,10 @@
  */
 
 #include "precompiled.h"
-#include "lib/bits.h"
+
+#include "bits.h"
+
+#include "lib/types.h"
 
 #include <cstring>