add lupan-wm and lupan-clock and use them if available

lupan-clock/Makefile

@@ -0,0 +1,2 @@
+lupan-clock: lupan-clock.c
+	${CC} -o $@ $< -lX11 -Wall

lupan-clock/lupan-clock.c

@@ -0,0 +1,44 @@
+#include <X11/Xlib.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <time.h>
+#include <unistd.h>
+#include <string.h>
+
+static void die(const char *errstr);
+
+void die(const char *errstr) {
+	fputs(errstr, stderr);
+	exit(EXIT_FAILURE);
+}
+
+void show(Display *dpy, int root, struct tm *tm)
+{
+	char s[6];
+	strftime(s, sizeof(s), "%H:%M", tm);
+        XStoreName(dpy, root, s);
+	XSync(dpy, True);
+}
+
+int main() {
+	Display *dpy;
+	int root, h, m, init = 60;
+	time_t t;
+	struct tm *tm;
+
+	if (!(dpy = XOpenDisplay(NULL)))
+		die("lupan-clock: cannot open display\n");
+	root = DefaultRootWindow(dpy);
+	while (1) {
+		t = time(NULL);
+		tm = localtime(&t);
+		if (tm->tm_hour != h || tm->tm_min != m || init > 0) {
+			show(dpy, root, tm);
+			h = tm->tm_hour;
+			m = tm->tm_min;
+			init = (init > 0) ? init - 1 : 0;
+		}
+		sleep(1);
+	}
+	return 1;
+}