*: make exec failure message more consistent

Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>

networking/nc_bloaty.c

@@ -230,7 +230,7 @@ static int doexec(char **proggie)
 	/* dup2(0, 2); - do we *really* want this? NO!
 	 * exec'ed prog can do it yourself, if needed */
 	execvp(proggie[0], proggie);
-	bb_perror_msg_and_die("exec");
+	bb_perror_msg_and_die("can't execute '%s'", proggie[0]);
 }
 
 /* connect_w_timeout: