diff --git a/headers/build/os/support/SupportDefs.h b/headers/build/os/support/SupportDefs.h
index f347e5bbc7..795001de40 100644
--- a/headers/build/os/support/SupportDefs.h
+++ b/headers/build/os/support/SupportDefs.h
@@ -1,49 +1,28 @@
-//------------------------------------------------------------------------------
-//	Copyright (c) 2004-2005, Haiku
-//
-//	Permission is hereby granted, free of charge, to any person obtaining a
-//	copy of this software and associated documentation files (the "Software"),
-//	to deal in the Software without restriction, including without limitation
-//	the rights to use, copy, modify, merge, publish, distribute, sublicense,
-//	and/or sell copies of the Software, and to permit persons to whom the
-//	Software is furnished to do so, subject to the following conditions:
-//
-//	The above copyright notice and this permission notice shall be included in
-//	all copies or substantial portions of the Software.
-//
-//	THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
-//	IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
-//	FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
-//	AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
-//	LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
-//	FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
-//	DEALINGS IN THE SOFTWARE.
-//
-//	File Name:		SupportDefs.h
-//	Author:			Erik Jaesler (erik@cgsoftware.com)
-//	Description:	Common type definitions.
-//------------------------------------------------------------------------------
-
+/*
+ * Copyright 2004-2007, Haiku, Inc. All Rights Reserved.
+ * Distributed under the terms of the MIT License.
+ *
+ * Author:
+ *		Erik Jaesler (erik@cgsoftware.com)
+ */
 #ifndef _SUPPORT_DEFS_H
 #define _SUPPORT_DEFS_H
 
-/* this !must! be located before the include of sys/types.h */
+
+/* this must be located before the include of sys/types.h */
 #if !defined(_SYS_TYPES_H) && !defined(_SYS_TYPES_H_)
 typedef unsigned long			ulong;
 typedef unsigned int			uint;
 typedef unsigned short			ushort;
 #endif
 
-
-// Standard Includes -----------------------------------------------------------
-
-// System Includes -------------------------------------------------------------
 #include <BeBuild.h>
-#include <sys/types.h>
 #include <Errors.h>
 
-// Shorthand type formats ------------------------------------------------------
+#include <sys/types.h>
 
+
+// Shorthand type formats
 typedef	signed char				int8;
 typedef unsigned char			uint8;
 typedef volatile signed char   	vint8;
@@ -59,9 +38,9 @@ typedef unsigned long			uint32;
 typedef volatile long			vint32;
 typedef volatile unsigned long	vuint32;
 
-typedef	long long					int64;
-typedef unsigned long long			uint64;
-typedef volatile long long			vint64;
+typedef	long long				int64;
+typedef unsigned long long		uint64;
+typedef volatile long long		vint64;
 typedef volatile unsigned long long	vuint64;
 
 typedef volatile long			vlong;
@@ -78,24 +57,20 @@ typedef unsigned char			uchar;
 typedef unsigned short          unichar;
 
 
-// Descriptive formats ---------------------------------------------------------
+// Descriptive formats
 typedef int32					status_t;
 typedef int64					bigtime_t;
 typedef uint32					type_code;
 typedef uint32					perform_code;
 
 
-// Empty string ("") -----------------------------------------------------------
+// Empty string ("")
 #ifdef __cplusplus
-extern _IMPEXP_BE const char *B_EMPTY_STRING;
+extern const char *B_EMPTY_STRING;
 #endif
 
 
-// min and max comparisons -----------------------------------------------------
-//	min() and max() won't work in C++
-#define min_c(a,b) ((a)>(b)?(b):(a))
-#define max_c(a,b) ((a)>(b)?(a):(b))
-
+// min and max comparisons
 #ifndef __cplusplus
 #	ifndef min
 #		define min(a,b) ((a)>(b)?(b):(a))
@@ -105,8 +80,12 @@ extern _IMPEXP_BE const char *B_EMPTY_STRING;
 #	endif
 #endif 
 
+// min() and max() won't work in C++
+#define min_c(a,b) ((a)>(b)?(b):(a))
+#define max_c(a,b) ((a)>(b)?(a):(b))
 
-// Grandfathering --------------------------------------------------------------
+
+// Grandfathering
 #ifndef __cplusplus
 #	include <stdbool.h>
 #endif 
@@ -116,34 +95,33 @@ extern _IMPEXP_BE const char *B_EMPTY_STRING;
 #endif
 
 
-//------------------------------------------------------------------------------
 #ifdef __cplusplus
 extern "C" {
 #endif
 
-//----- Atomic functions; old value is returned --------------------------------
-extern _IMPEXP_ROOT int32	atomic_set(vint32 *value, int32 newValue);
-extern _IMPEXP_ROOT int32	atomic_test_and_set(vint32 *value, int32 newValue, int32 testAgainst);
-extern _IMPEXP_ROOT int32	atomic_add(vint32 *value, int32 addValue);
-extern _IMPEXP_ROOT int32	atomic_and(vint32 *value, int32 andValue);
-extern _IMPEXP_ROOT int32	atomic_or(vint32 *value, int32 orValue);	
-extern _IMPEXP_ROOT int32	atomic_get(vint32 *value);
+// Atomic functions; previous value is returned
+extern int32	atomic_set(vint32 *value, int32 newValue);
+extern int32	atomic_test_and_set(vint32 *value, int32 newValue, int32 testAgainst);
+extern int32	atomic_add(vint32 *value, int32 addValue);
+extern int32	atomic_and(vint32 *value, int32 andValue);
+extern int32	atomic_or(vint32 *value, int32 orValue);	
+extern int32	atomic_get(vint32 *value);
 
-extern _IMPEXP_ROOT int64	atomic_set64(vint64 *value, int64 newValue);
-extern _IMPEXP_ROOT int64	atomic_test_and_set64(vint64 *value, int64 newValue, int64 testAgainst);
-extern _IMPEXP_ROOT int64	atomic_add64(vint64 *value, int64 addValue);
-extern _IMPEXP_ROOT int64	atomic_and64(vint64 *value, int64 andValue);
-extern _IMPEXP_ROOT int64	atomic_or64(vint64 *value, int64 orValue);	
-extern _IMPEXP_ROOT int64	atomic_get64(vint64 *value);
+extern int64	atomic_set64(vint64 *value, int64 newValue);
+extern int64	atomic_test_and_set64(vint64 *value, int64 newValue, int64 testAgainst);
+extern int64	atomic_add64(vint64 *value, int64 addValue);
+extern int64	atomic_and64(vint64 *value, int64 andValue);
+extern int64	atomic_or64(vint64 *value, int64 orValue);	
+extern int64	atomic_get64(vint64 *value);
 
-// Other stuff -----------------------------------------------------------------
-extern _IMPEXP_ROOT void *	get_stack_frame(void);
+// Other stuff
+extern void*	get_stack_frame(void);
 
 #ifdef __cplusplus
 }
 #endif
 
-//-------- Obsolete or discouraged API -----------------------------------------
+// Obsolete or discouraged API
 
 // use 'true' and 'false'
 #ifndef FALSE