Index: contrib/libxo/libxo/libxo.c
===================================================================
--- contrib/libxo/libxo/libxo.c
+++ contrib/libxo/libxo/libxo.c
@@ -42,6 +42,7 @@
 #include <ctype.h>
 #include <wctype.h>
 #include <getopt.h>
+#include <stdbool.h>
 
 #include "xo_config.h"
 #include "xo.h"
@@ -268,6 +269,7 @@
     char *xo_gt_domain;		/* Gettext domain, suitable for dgettext(3) */
     xo_encoder_func_t xo_encoder; /* Encoding function */
     void *xo_private;		/* Private data for external encoders */
+    bool xo_libxo_set;		/* Initial flags passed via --libxo */
 };
 
 /* Flag operations */
@@ -8170,6 +8172,7 @@
     }
 
     xo_handle_t *xop = xo_default(NULL);
+    xop->xo_libxo_set = false;
 
     for (save = i = 1; i < argc; i++) {
 	if (argv[i] == NULL
@@ -8180,6 +8183,7 @@
 	    continue;
 	}
 
+	xop->xo_libxo_set = true;
 	cp = argv[i] + sizeof(libxo_opt) - 1;
 	if (*cp == '\0') {
 	    cp = argv[++i];
@@ -8224,6 +8228,17 @@
     return save;
 }
 
+/*
+ * Let consumers know if --libxo was passed in argv.
+ */
+bool
+xo_libxo_set(void)
+{
+    xo_handle_t *xop = xo_default(NULL);
+
+    return (xop->xo_libxo_set);
+}
+
 /*
  * Debugging function that dumps the current stack of open libxo constructs,
  * suitable for calling from the debugger.
Index: contrib/libxo/libxo/xo.h
===================================================================
--- contrib/libxo/libxo/xo.h
+++ contrib/libxo/libxo/xo.h
@@ -26,6 +26,7 @@
 #include <limits.h>
 #include <stdlib.h>
 #include <errno.h>
+#include <stdbool.h>
 
 #ifdef __dead2
 #define NORETURN __dead2
@@ -583,6 +584,9 @@
 int
 xo_parse_args (int argc, char **argv);
 
+bool
+xo_libxo_set(void);
+
 /**
  * This is the "magic" number returned by libxo-supporting commands
  * when passed the equally magic "--libxo-check" option.  If you
Index: usr.bin/w/w.c
===================================================================
--- usr.bin/w/w.c
+++ usr.bin/w/w.c
@@ -95,7 +95,6 @@
 static struct winsize ws;
 static kvm_t   *kd;
 static time_t	now;		/* the current time of day */
-static int	ttywidth;	/* width of tty */
 static int	fromwidth = 0;	/* max width of "from" field */
 static int	argwidth;	/* width of arguments */
 static int	header = 1;	/* true if -h flag: don't print heading */
@@ -381,13 +380,21 @@
 			}
 		}
 	}
-	if ((ioctl(STDOUT_FILENO, TIOCGWINSZ, &ws) == -1 &&
-	     ioctl(STDERR_FILENO, TIOCGWINSZ, &ws) == -1 &&
-	     ioctl(STDIN_FILENO, TIOCGWINSZ, &ws) == -1) || ws.ws_col == 0)
-	       ttywidth = 79;
-        else
-	       ttywidth = ws.ws_col - 1;
-	argwidth = ttywidth - WUSED;
+	/* Don't truncate the argument list if --libxo was specified */
+	if (xo_libxo_set()) {
+		argwidth = ARG_MAX;
+	} else {
+		int	ttywidth;	/* width of tty */
+
+		if ((ioctl(STDOUT_FILENO, TIOCGWINSZ, &ws) == -1 &&
+		    ioctl(STDERR_FILENO, TIOCGWINSZ, &ws) == -1 &&
+		    ioctl(STDIN_FILENO, TIOCGWINSZ, &ws) == -1) ||
+		    ws.ws_col == 0)
+			ttywidth = 79;
+		else
+			ttywidth = ws.ws_col - 1;
+		argwidth = ttywidth - WUSED;
+	}
 	if (argwidth < 4)
 		argwidth = 8;
 	for (ep = ehead; ep != NULL; ep = ep->next) {