diff --git a/usr.bin/stdbuf/stdbuf.c b/usr.bin/stdbuf/stdbuf.c
index ecbcd50a64fb..d80555fd7a5e 100644
--- a/usr.bin/stdbuf/stdbuf.c
+++ b/usr.bin/stdbuf/stdbuf.c
@@ -1,112 +1,110 @@
 /*-
  * SPDX-License-Identifier: BSD-2-Clause
  *
  * Copyright (c) 2012 Jeremie Le Hen <jlh@FreeBSD.org>
  * All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
  * are met:
  * 1. Redistributions of source code must retain the above copyright
  *    notice, this list of conditions and the following disclaimer.
  * 2. Redistributions in binary form must reproduce the above copyright
  *    notice, this list of conditions and the following disclaimer in the
  *    documentation and/or other materials provided with the distribution.
  *
  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  * SUCH DAMAGE.
  *
  * $FreeBSD$
  */
 
 #include <err.h>
 #include <stdio.h>
 #include <stdlib.h>
 #include <unistd.h>
 
 #define	LIBSTDBUF	"/usr/lib/libstdbuf.so"
 #define	LIBSTDBUF32	"/usr/lib32/libstdbuf.so"
 
-extern char *__progname;
+static int
+appendenv(const char *key, const char *value)
+{
+	char *curval, *newpair;
+	int ret;
+
+	curval = getenv(key);
+	if (curval == NULL)
+		ret = asprintf(&newpair, "%s=%s", key, value);
+	else
+		ret = asprintf(&newpair, "%s=%s:%s", key, curval, value);
+	if (ret > 0)
+		ret = putenv(newpair);
+	if (ret < 0)
+		warn("Failed to set environment variable: %s", key);
+	return (ret);
+}
 
 static void
-usage(int s)
+usage(void)
 {
 
-	fprintf(stderr, "Usage: %s [-e 0|L|B|<sz>] [-i 0|L|B|<sz>] [-o 0|L|B|<sz>] "
-	    "<cmd> [args ...]\n", __progname);
-	exit(s);
+	fprintf(stderr,
+	    "usage: stdbuf [-e 0|L|B|<sz>] [-i 0|L|B|<sz>] [-o 0|L|B|<sz>] "
+	    "<cmd> [args ...]\n");
+	exit(1);
 }
 
 int
 main(int argc, char *argv[])
 {
 	char *ibuf, *obuf, *ebuf;
-	char *preload0, *preload1;
 	int i;
 
 	ibuf = obuf = ebuf = NULL;
 	while ((i = getopt(argc, argv, "e:i:o:")) != -1) {
 		switch (i) {
 		case 'e':
 			ebuf = optarg;
 			break;
 		case 'i':
 			ibuf = optarg;
 			break;
 		case 'o':
 			obuf = optarg;
 			break;
-		case '?':
 		default:
-			usage(1);
+			usage();
 			break;
 		}
 	}
 	argc -= optind;
 	argv += optind;
 	if (argc == 0)
 		exit(0);
 
 	if (ibuf != NULL && setenv("_STDBUF_I", ibuf, 1) == -1)
 		warn("Failed to set environment variable: %s=%s",
 		    "_STDBUF_I", ibuf);
 	if (obuf != NULL && setenv("_STDBUF_O", obuf, 1) == -1)
 		warn("Failed to set environment variable: %s=%s",
 		    "_STDBUF_O", obuf);
 	if (ebuf != NULL && setenv("_STDBUF_E", ebuf, 1) == -1)
 		warn("Failed to set environment variable: %s=%s",
 		    "_STDBUF_E", ebuf);
 
-	preload0 = getenv("LD_PRELOAD");
-	if (preload0 == NULL)
-		i = asprintf(&preload1, "LD_PRELOAD=" LIBSTDBUF);
-	else
-		i = asprintf(&preload1, "LD_PRELOAD=%s:%s", preload0,
-		    LIBSTDBUF);
-
-	if (i < 0 || putenv(preload1) == -1)
-		warn("Failed to set environment variable: LD_PRELOAD");
-
-	preload0 = getenv("LD_32_PRELOAD");
-	if (preload0 == NULL)
-		i = asprintf(&preload1, "LD_32_PRELOAD=" LIBSTDBUF32);
-	else
-		i = asprintf(&preload1, "LD_32_PRELOAD=%s:%s", preload0,
-		    LIBSTDBUF32);
-
-	if (i < 0 || putenv(preload1) == -1)
-		warn("Failed to set environment variable: LD_32_PRELOAD");
+	appendenv("LD_PRELOAD", LIBSTDBUF);
+	appendenv("LD_32_PRELOAD", LIBSTDBUF32);
 
 	execvp(argv[0], argv);
 	err(2, "%s", argv[0]);
 }