getatomprop: Add forward declaration
No functional changes, but for every other function we have a forward
declaration here. getatomprop should be no exception.
@@ -169,6 +169,7 @@ static void focus(Client *c);
static void focusin(XEvent *e);
static void focusmon(const Arg *arg);
static void focusstack(const Arg *arg);
+static Atom getatomprop(Client *c, Atom prop);
static int getrootptr(int *x, int *y);
static long getstate(Window w);
static int gettextprop(Window w, Atom atom, char *text, unsigned int size);
