headers/build: Use the system's types.h on Haiku.

Technically a "hack" (but then again most of the config/build stuff is);
as we need to use the system's config/types.h in order to get stdint
definitions and the like.

Previously there was a config_build directory which allowed the existence
of two types.h -- the system one, and the headers/build one, but seeing
as we only need this to provide Haiku-specific core types on other platforms,
using the system's one should be fine.

Our core type definitions have not changed in some time (and it's unclear
when they would change aside from potential new platforms), breakage of the
Haiku-on-Haiku build due to this should not happen often (if ever.)

headers/build/config/types.h

@@ -2,7 +2,9 @@
  * Copyright 2009-2011, Haiku, Inc. All Rights Reserved.
  * Distributed under the terms of the MIT License.
  */
-#ifndef _CONFIG_BUILD_TYPES_H
+#ifdef HAIKU_HOST_PLATFORM_HAIKU
+#include_next <config/types.h>
+#elif !defined(_CONFIG_BUILD_TYPES_H)
 #define _CONFIG_BUILD_TYPES_H
 
 

headers/build/host/haiku_host/Errors.h

@@ -1 +0,0 @@
-#include "../os/support/Errors.h"

headers/build/host/haiku_host/config_build/HaikuConfig.h

@@ -1 +0,0 @@
-#include "/boot/system/develop/headers/config/HaikuConfig.h"

headers/build/host/haiku_host/config_build/types.h

@@ -1 +0,0 @@
-#include "/boot/system/develop/headers/config/types.h"