[includes] Move enum_bitfields.h to base includes

Pull this widely-useful header out of kutil, so more things can use it.
Also replace its dependency on <type_traits> by defining our own custom
basic_types.h which contains a subset of the standard's types.

src/kernel/acpi_tables.h

@@ -3,8 +3,8 @@
 #include <stddef.h>
 #include <stdint.h>
 
+#include "enum_bitfields.h"
 #include "kutil/coord.h"
-#include "kutil/enum_bitfields.h"
 #include "kutil/misc.h"
 
 struct acpi_table_header

src/kernel/apic.h

@@ -3,7 +3,7 @@
 /// Classes to control both local and I/O APICs.
 
 #include <stdint.h>
-#include "kutil/enum_bitfields.h"
+#include "enum_bitfields.h"
 
 enum class isr : uint8_t;
 

src/kernel/gdt.h

@@ -3,7 +3,7 @@
 /// Definitions relating to a CPU's GDT table
 #include <stdint.h>
 
-#include "kutil/enum_bitfields.h"
+#include "enum_bitfields.h"
 
 class TSS;
 

src/kernel/memory_bootstrap.cpp

@@ -3,8 +3,8 @@
 #include "kernel_args.h"
 #include "j6/init.h"
 
+#include "enum_bitfields.h"
 #include "kutil/assert.h"
-#include "kutil/enum_bitfields.h"
 #include "kutil/heap_allocator.h"
 #include "kutil/no_construct.h"
 

src/kernel/objects/vm_area.h

@@ -5,8 +5,8 @@
 #include <stddef.h>
 #include <stdint.h>
 
+#include "enum_bitfields.h"
 #include "j6/signals.h"
-#include "kutil/enum_bitfields.h"
 #include "kutil/vector.h"
 
 #include "kernel_memory.h"

src/kernel/page_table.h

@@ -3,7 +3,7 @@
 /// Helper structures for dealing with page tables.
 
 #include <stdint.h>
-#include "kutil/enum_bitfields.h"
+#include "enum_bitfields.h"
 #include "kernel_memory.h"
 
 struct free_page_header;

src/kernel/vm_space.h

@@ -3,7 +3,7 @@
 /// Structure for tracking a range of virtual memory addresses
 
 #include <stdint.h>
-#include "kutil/enum_bitfields.h"
+#include "enum_bitfields.h"
 #include "kutil/spinlock.h"
 #include "kutil/vector.h"
 #include "page_table.h"