diff --git a/lib/libc/gen/check_utility_compat.c b/lib/libc/gen/check_utility_compat.c
index 0ccdec115a87..04c594b52665 100644
--- a/lib/libc/gen/check_utility_compat.c
+++ b/lib/libc/gen/check_utility_compat.c
@@ -35,32 +35,28 @@ __FBSDID("$FreeBSD$");
  * are threaded, so I'm not concerned about cancellation points or other
  * niceties.
  */
+#include <sys/limits.h>
+
 #include <limits.h>
 #include <stdlib.h>
 #include <string.h>
 #include <unistd.h>
 
-#ifndef LINE_MAX
-#define	LINE_MAX _POSIX2_LINE_MAX
-#endif
-
 #define	_PATH_UTIL_COMPAT	"/etc/compat-FreeBSD-4-util"
 #define	_ENV_UTIL_COMPAT	"_COMPAT_FreeBSD_4"
 
 int
 check_utility_compat(const char *utility)
 {
-	char buf[LINE_MAX];
+	char buf[PATH_MAX];
 	char *p, *bp;
 	int len;
 
 	if ((p = getenv(_ENV_UTIL_COMPAT)) != NULL) {
 		strlcpy(buf, p, sizeof buf);
 	} else {
-		if ((len = readlink(_PATH_UTIL_COMPAT, buf, sizeof buf)) < 0)
+		if ((len = readlink(_PATH_UTIL_COMPAT, buf, sizeof(buf) - 1)) < 0)
 			return 0;
-		if (len > sizeof buf)
-			len = sizeof buf;
 		buf[len] = '\0';
 	}
 	if (buf[0] == '\0')