demo: don't use symlinks for x/tools compatible

_demo/cgofull/foo.c

@@ -0,0 +1,12 @@
+#include <stdio.h>
+#include "foo.h"
+
+void print_foo(Foo *f)
+{
+	printf("print_foo: %d\n", f->a);
+}
+
+int c_callback(int i)
+{
+	return i + 1;
+}