add stub routines

src/libmemdraw/draw-stub.c

@@ -0,0 +1,27 @@
+#include <u.h>
+#include <libc.h>
+#include <draw.h>
+#include <memdraw.h>
+
+void
+memimagedraw(Memimage *dst, Rectangle r, Memimage *src, Point sp, Memimage *mask, Point mp, int op)
+{
+	Memdrawparam *par;
+	
+	if((par = _memimagedrawsetup(dst, r, src, sp, mask, mp, op)) == nil)
+		return;
+	_memimagedraw(par);
+}
+
+void
+memfillcolor(Memimage *m, u32int val)
+{
+	_memfillcolor(m, val);
+}
+
+u32int
+pixelbits(Memimage *m, Point p)
+{
+	return _pixelbits(m, p);
+}
+