diff --git a/lib/libutils/isoc/include/sys/_default_fcntl.h b/lib/libutils/isoc/include/sys/_default_fcntl.h
deleted file mode 100644
index fafa79fd574..00000000000
--- a/lib/libutils/isoc/include/sys/_default_fcntl.h
+++ /dev/null
@@ -1,77 +0,0 @@
-/* SPDX-License-Identifier: BSD-3-Clause */
-/*
- * Copyright (c) 1994-2009  Red Hat, Inc. All rights reserved.
- */
-
-#ifndef	_SYS__DEFAULT_FCNTL_H_
-#ifdef __cplusplus
-extern "C" {
-#endif
-#define	_SYS__DEFAULT_FCNTL_H_
-#include <_ansi.h>
-#include <sys/cdefs.h>
-#define	_FOPEN		(-1)	/* from sys/file.h, kernel use only */
-#define	_FREAD		0x0001	/* read enabled */
-#define	_FWRITE		0x0002	/* write enabled */
-#define	_FAPPEND	0x0008	/* append (writes guaranteed at the end) */
-#define	_FMARK		0x0010	/* internal; mark during gc() */
-#define	_FDEFER		0x0020	/* internal; defer for next gc pass */
-#define	_FASYNC		0x0040	/* signal pgrp when data ready */
-#define	_FSHLOCK	0x0080	/* BSD flock() shared lock present */
-#define	_FEXLOCK	0x0100	/* BSD flock() exclusive lock present */
-#define	_FCREAT		0x0200	/* open with file create */
-#define	_FTRUNC		0x0400	/* open with truncation */
-#define	_FEXCL		0x0800	/* error on open if file exists */
-#define	_FNBIO		0x1000	/* non blocking I/O (sys5 style) */
-#define	_FSYNC		0x2000	/* do all writes synchronously */
-#define	_FNONBLOCK	0x4000	/* non blocking I/O (POSIX style) */
-#define	_FNDELAY	_FNONBLOCK	/* non blocking I/O (4.2 style) */
-#define	_FNOCTTY	0x8000	/* don't assign a ctty on this open */
-#define	_FNOINHERIT	0x40000
-#define	_FDIRECT	0x80000
-#define	_FNOFOLLOW	0x100000
-#define	_FDIRECTORY	0x200000
-#define	_FEXECSRCH	0x400000
-
-#define	O_ACCMODE	(O_RDONLY|O_WRONLY|O_RDWR)
-
-/*
- * Flag values for open(2) and fcntl(2)
- * The kernel adds 1 to the open modes to turn it into some
- * combination of FREAD and FWRITE.
- */
-#define	O_RDONLY	0		/* +1 == FREAD */
-#define	O_WRONLY	1		/* +1 == FWRITE */
-#define	O_RDWR		2		/* +1 == FREAD|FWRITE */
-#define	O_APPEND	_FAPPEND
-#define	O_CREAT		_FCREAT
-#define	O_TRUNC		_FTRUNC
-#define	O_EXCL		_FEXCL
-#define O_SYNC		_FSYNC
-/*	O_NDELAY	_FNDELAY 	set in include/fcntl.h */
-/*	O_NDELAY	_FNBIO 		set in include/fcntl.h */
-#define	O_NONBLOCK	_FNONBLOCK
-#define	O_NOCTTY	_FNOCTTY
-
-/* XXX close on exec request; must match UF_EXCLOSE in user.h */
-#define	FD_CLOEXEC	1	/* posix */
-
-/* fcntl(2) requests */
-#define	F_DUPFD		0	/* Duplicate fildes */
-#define	F_GETFD		1	/* Get fildes flags (close on exec) */
-#define	F_SETFD		2	/* Set fildes flags (close on exec) */
-#define	F_GETFL		3	/* Get file flags */
-#define	F_SETFL		4	/* Set file flags */
-#define	F_GETLK  	7	/* Get record-locking information */
-#define	F_SETLK  	8	/* Set or Clear a record-lock (Non-Blocking) */
-#define	F_SETLKW 	9	/* Set or Clear a record-lock (Blocking) */
-
-/* fcntl(2) flags (l_type field of flock structure) */
-#define	F_RDLCK		1	/* read lock */
-#define	F_WRLCK		2	/* write lock */
-#define	F_UNLCK		3	/* remove lock(s) */
-
-#ifdef __cplusplus
-}
-#endif
-#endif	/* !_SYS__DEFAULT_FCNTL_H_ */
diff --git a/lib/libutils/isoc/include/sys/fcntl.h b/lib/libutils/isoc/include/sys/fcntl.h
index 604f8244fd8..8ff76980e56 100644
--- a/lib/libutils/isoc/include/sys/fcntl.h
+++ b/lib/libutils/isoc/include/sys/fcntl.h
@@ -5,5 +5,19 @@
 
 #ifndef _SYS_FCNTL_H_
 #define _SYS_FCNTL_H_
-#include <sys/_default_fcntl.h>
+
+#define	_FAPPEND	0x0008	/* append (writes guaranteed at the end) */
+#define	_FCREAT		0x0200	/* open with file create */
+#define	_FTRUNC		0x0400	/* open with truncation */
+
+/*
+ * Flag values for open(2) and fcntl(2)
+ */
+#define	O_RDONLY	0		/* +1 == FREAD */
+#define	O_WRONLY	1		/* +1 == FWRITE */
+#define	O_RDWR		2		/* +1 == FREAD|FWRITE */
+#define	O_APPEND	_FAPPEND
+#define	O_CREAT		_FCREAT
+#define	O_TRUNC		_FTRUNC
+
 #endif /* _SYS_FCNTL_H_ */