add select(2)-based i/o multiplexing

std.c

@@ -263,13 +263,23 @@ ungetch(int c) {
 
 int
 main(int argc, char *argv[]) {
+	fd_set rfds;
+	int r;
+
 	if(argc == 2 && !strcmp("-v", argv[1]))
 		eprint("std-"VERSION", © 2008 Matthias-Christian Ott\n");
 	else if(argc == 1)
 		eprint("usage: st [-v]\n");
 	getpty();
 	shell();
+	FD_ZERO(&rfds);
+	FD_SET(STDIN_FILENO, &rfds);
+	FD_SET(ptm, &rfds);
 	for(;;) {
+		r = select(ptm + 1, &rfds, NULL, NULL, NULL);
+		if(r == -1)
+			eprintn("error, cannot select");
+		if(FD_ISSET(ptm, &rfds)) {
 			c = getch();
 			switch(c) {
 			case '\033':
@@ -278,6 +288,8 @@ main(int argc, char *argv[]) {
 			default:
 				putchar(c);
 			}
+			fflush(stdout);
+		}
 	}
 	return 0;
 }