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+/* Copyright (C) 1991, 1992, 1993 Free Software Foundation, Inc.
+This file is part of the GNU C Library.
+
+The GNU C Library is free software; you can redistribute it and/or
+modify it under the terms of the GNU Library General Public License as
+published by the Free Software Foundation; either version 2 of the
+License, or (at your option) any later version.
+
+The GNU C Library is distributed in the hope that it will be useful,
+but WITHOUT ANY WARRANTY; without even the implied warranty of
+MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+Library General Public License for more details.
+
+You should have received a copy of the GNU Library General Public
+License along with the GNU C Library; see the file COPYING.LIB.  If
+not, write to the Free Software Foundation, Inc., 675 Mass Ave,
+Cambridge, MA 02139, USA.  */
+
+#ifndef	_FEATURES_H
+
+#define	_FEATURES_H	1
+
+/* These are defined by the user (or the compiler)
+   to specify the desired environment:
+
+   __STRICT_ANSI__	ANSI Standard C.
+   _POSIX_SOURCE	IEEE Std 1003.1.
+   _POSIX_C_SOURCE	If ==1, like _POSIX_SOURCE; if ==2 add IEEE Std 1003.2.
+   _BSD_SOURCE		ANSI, POSIX, and 4.3BSD things.
+   _SVID_SOURCE		ANSI, POSIX, and SVID things.
+   _GNU_SOURCE		All of the above, plus GNU extensions.
+
+   The `-ansi' switch to the GNU C compiler defines __STRICT_ANSI__.
+   If none of these are defined, the default is _GNU_SOURCE.
+   If more than one of these are defined, they accumulate.
+   For example __STRICT_ANSI__, _POSIX_SOURCE and _POSIX_C_SOURCE
+   together give you ANSI C, 1003.1, and 1003.2, but nothing else.
+
+   These are defined by this file and are used by the
+   header files to decide what to declare or define:
+
+   __USE_POSIX		Define IEEE Std 1003.1 things.
+   __USE_POSIX2		Define IEEE Std 1003.2 things.
+   __USE_BSD		Define 4.3BSD things.
+   __USE_SVID		Define SVID things.
+   __USE_MISC		Define things common to BSD and System V Unix.
+   __USE_GNU		Define GNU extensions.
+   __FAVOR_BSD		Favor 4.3BSD things in cases of conflict.
+
+   The macro `__GNU_LIBRARY__' is defined by this file unconditionally.
+
+   All macros defined by this file are defined as 1.
+   All macros listed above as possibly being defined by this file are
+   explicitly undefined if they are not explicitly defined.
+   Feature-test macros that are not defined by the user or compiler
+   but are implied by the other feature-test macros defined (or by the
+   lack of any definitions) are defined by the file.  */
+
+
+/* Undefine everything, so we get a clean slate.  */
+#undef	__USE_POSIX
+#undef	__USE_POSIX2
+#undef	__USE_BSD
+#undef	__USE_SVID
+#undef	__USE_MISC
+#undef	__USE_GNU
+#undef	__FAVOR_BSD
+
+
+/* If nothing is defined, define _GNU_SOURCE.  */
+#if (!defined(_GNU_SOURCE) && !defined(__STRICT_ANSI__) && \
+     !defined(_POSIX_SOURCE) && !defined(_POSIX_C_SOURCE) && \
+     !defined(_BSD_SOURCE) && !defined(_SVID_SOURCE))
+#define	_GNU_SOURCE	1
+#endif
+
+
+/* Always use ANSI things.  */
+#define	__USE_ANSI	1
+
+
+/* If _BSD_SOURCE was defined by the user, favor BSD over POSIX.  */
+#ifdef	_BSD_SOURCE
+#define	__FAVOR_BSD	1
+#endif
+
+
+/* If nothing (other than _GNU_SOURCE) is defined,
+   define _BSD_SOURCE and _SVID_SOURCE.  */
+#if (!defined(__STRICT_ANSI__) && !defined(_POSIX_SOURCE) && \
+     !defined(_POSIX_C_SOURCE) && !defined(_BSD_SOURCE) && \
+     !defined(_SVID_SOURCE))
+#define	_BSD_SOURCE	1
+#define	_SVID_SOURCE	1
+#endif
+
+/* If none of the ANSI/POSIX macros are defined, use POSIX.1 and POSIX.2.  */
+#if (!defined(__STRICT_ANSI__) && !defined(_POSIX_SOURCE) && \
+     !defined(_POSIX_C_SOURCE))
+#define	_POSIX_SOURCE	1
+#define	_POSIX_C_SOURCE	2
+#endif
+
+#if	defined(_POSIX_SOURCE) || _POSIX_C_SOURCE >= 1
+#define	__USE_POSIX	1
+#endif
+
+#if	defined(_POSIX_C_SOURCE) && _POSIX_C_SOURCE >= 2
+#define	__USE_POSIX2	1
+#endif
+
+#if defined(_BSD_SOURCE) || defined(_SVID_SOURCE)
+#define	__USE_MISC	1
+#endif
+
+#ifdef	_BSD_SOURCE
+#define	__USE_BSD	1
+#endif
+
+#ifdef	_SVID_SOURCE
+#define	__USE_SVID	1
+#endif
+
+#ifdef	_GNU_SOURCE
+#define	__USE_GNU	1
+#endif
+
+
+#undef	__GNU_LIBRARY__
+#define	__GNU_LIBRARY__	1
+
+
+#if	!defined(__GNUC__) || __GNUC__ < 2
+/* In GCC version 2, (__extension__ EXPR) will not complain
+   about GCC extensions used in EXPR under -ansi or -pedantic.  */
+#define	__extension__
+#endif
+
+
+/* This is here only because every header file already includes this one.  */
+#include <sys/cdefs.h>
+
+/* This is here only because every header file already includes this one.  */
+#ifndef _LIBC
+/* Get the definitions of all the appropriate `__stub_FUNCTION' symbols.
+   <stubs.h> contains `#define __stub_FUNCTION' when FUNCTION is a stub
+   which will always return failure (and set errno to ENOSYS).
+
+   We avoid including <stubs.h> when compiling the C library itself to
+   avoid a dependency loop.  stubs.h depends on every object file.  If
+   this #include were done for the library source code, then every object
+   file would depend on stubs.h.  */
+
+#include <stubs.h>
+#endif
+
+#endif	/* __features.h  */