Added main program, updated README.md

mwm.c

@@ -0,0 +1,18 @@
+#include <X11/Xlib.h>
+
+#define stok(s)     XKeysymToKeycode(d, XStringToKeysym(s))
+#define on(k, a)    if (e.xkey.keycode == stok(k)) { a; continue; }
+#define grab(k, m)  XGrabKey (d, stok(k), m, r, 1, 1, 1)
+
+int main (int argc, char **argv) {
+  Display *d = XOpenDisplay(0); Window r = DefaultRootWindow(d); XEvent e;
+  XSelectInput (d, r, SubstructureRedirectMask);
+
+  grab ("KEY", MODIFIER);
+
+  while (!XNextEvent (d, &e)) {
+    if (e.type == KeyPress) {
+      on (KEY, ACTIONS);
+    }
+  }
+}