Refactor wins_launch_external()

Allow for passing an arbitrary number of arguments. This also allows us
to remove wins_launch_external2() and use wins_launch_external() at all
call sites instead.

Signed-off-by: Lukas Fleischer <calcurse@cryptocrack.de>

src/io.c

@@ -1175,8 +1175,10 @@ void io_log_display(struct io_file *log, const char *msg,
 				child_wait(NULL, NULL, pid);
 		}
 	} else {
-		if (status_ask_bool(msg) == 1)
-			wins_launch_external(log->name, pager);
+		if (status_ask_bool(msg) == 1) {
+			const char *arg[] = { pager, log->name, NULL };
+			wins_launch_external(arg);
+		}
 		wins_erase_status_bar();
 	}
 }