diff --git a/include/lib/libc/errno.h b/include/lib/libc/errno.h
index ad140ab..029912f 100644
--- a/include/lib/libc/errno.h
+++ b/include/lib/libc/errno.h
@@ -36,17 +36,13 @@
  *	@(#)errno.h	8.5 (Berkeley) 1/21/94
  * $FreeBSD$
  */
+/*
+ * Portions copyright (c) 2018, ARM Limited and Contributors.
+ * All rights reserved.
+ */
 
-#ifndef _SYS_ERRNO_H_
-#define _SYS_ERRNO_H_
-
-#if !defined(_KERNEL) && !defined(_STANDALONE)
-#include <sys/cdefs.h>
-__BEGIN_DECLS
-int *	__error(void);
-__END_DECLS
-#define	errno		(* __error())
-#endif
+#ifndef ERRNO_H
+#define ERRNO_H
 
 #define	EPERM		1		/* Operation not permitted */
 #define	ENOENT		2		/* No such file or directory */
@@ -63,9 +59,7 @@
 #define	ENOMEM		12		/* Cannot allocate memory */
 #define	EACCES		13		/* Permission denied */
 #define	EFAULT		14		/* Bad address */
-#ifndef _POSIX_SOURCE
 #define	ENOTBLK		15		/* Block device required */
-#endif
 #define	EBUSY		16		/* Device busy */
 #define	EEXIST		17		/* File exists */
 #define	EXDEV		18		/* Cross-device link */
@@ -76,9 +70,7 @@
 #define	ENFILE		23		/* Too many open files in system */
 #define	EMFILE		24		/* Too many open files */
 #define	ENOTTY		25		/* Inappropriate ioctl for device */
-#ifndef _POSIX_SOURCE
 #define	ETXTBSY		26		/* Text file busy */
-#endif
 #define	EFBIG		27		/* File too large */
 #define	ENOSPC		28		/* No space left on device */
 #define	ESPIPE		29		/* Illegal seek */
@@ -92,7 +84,6 @@
 
 /* non-blocking and interrupt i/o */
 #define	EAGAIN		35		/* Resource temporarily unavailable */
-#ifndef _POSIX_SOURCE
 #define	EWOULDBLOCK	EAGAIN		/* Operation would block */
 #define	EINPROGRESS	36		/* Operation now in progress */
 #define	EALREADY	37		/* Operation already in progress */
@@ -127,18 +118,14 @@
 #define	ECONNREFUSED	61		/* Connection refused */
 
 #define	ELOOP		62		/* Too many levels of symbolic links */
-#endif /* _POSIX_SOURCE */
 #define	ENAMETOOLONG	63		/* File name too long */
 
 /* should be rearranged */
-#ifndef _POSIX_SOURCE
 #define	EHOSTDOWN	64		/* Host is down */
 #define	EHOSTUNREACH	65		/* No route to host */
-#endif /* _POSIX_SOURCE */
 #define	ENOTEMPTY	66		/* Directory not empty */
 
 /* quotas & mush */
-#ifndef _POSIX_SOURCE
 #define	EPROCLIM	67		/* Too many processes */
 #define	EUSERS		68		/* Too many users */
 #define	EDQUOT		69		/* Disc quota exceeded */
@@ -151,12 +138,10 @@
 #define	EPROGUNAVAIL	74		/* RPC prog. not avail */
 #define	EPROGMISMATCH	75		/* Program version wrong */
 #define	EPROCUNAVAIL	76		/* Bad procedure for program */
-#endif /* _POSIX_SOURCE */
 
 #define	ENOLCK		77		/* No locks available */
 #define	ENOSYS		78		/* Function not implemented */
 
-#ifndef _POSIX_SOURCE
 #define	EFTYPE		79		/* Inappropriate file type or format */
 #define	EAUTH		80		/* Authentication error */
 #define	ENEEDAUTH	81		/* Need authenticator */
@@ -168,41 +153,17 @@
 #define	ENOATTR		87		/* Attribute not found */
 
 #define	EDOOFUS		88		/* Programming error */
-#endif /* _POSIX_SOURCE */
 
 #define	EBADMSG		89		/* Bad message */
 #define	EMULTIHOP	90		/* Multihop attempted */
 #define	ENOLINK		91		/* Link has been severed */
 #define	EPROTO		92		/* Protocol error */
 
-#ifndef _POSIX_SOURCE
 #define	ENOTCAPABLE	93		/* Capabilities insufficient */
 #define	ECAPMODE	94		/* Not permitted in capability mode */
 #define	ENOTRECOVERABLE	95		/* State not recoverable */
 #define	EOWNERDEAD	96		/* Previous owner died */
-#endif /* _POSIX_SOURCE */
 
-#ifndef _POSIX_SOURCE
 #define	ELAST		96		/* Must be equal largest errno */
-#endif /* _POSIX_SOURCE */
 
-#if defined(_KERNEL) || defined(_WANT_KERNEL_ERRNO)
-/* pseudo-errors returned inside kernel to modify return to process */
-#define	ERESTART	(-1)		/* restart syscall */
-#define	EJUSTRETURN	(-2)		/* don't modify regs, just return */
-#define	ENOIOCTL	(-3)		/* ioctl not handled by this layer */
-#define	EDIRIOCTL	(-4)		/* do direct ioctl in GEOM */
-#define	ERELOOKUP	(-5)		/* retry the directory lookup */
-#endif
-
-#ifndef _KERNEL
-#if __EXT1_VISIBLE
-/* ISO/IEC 9899:2011 K.3.2.2 */
-#ifndef _ERRNO_T_DEFINED
-#define _ERRNO_T_DEFINED
-typedef int errno_t;
-#endif
-#endif /* __EXT1_VISIBLE */
-#endif
-
-#endif
+#endif /* ERRNO_H */