Add arbitrary precision integer support.
Some functionality is still missing (eg and, or, bit shift), and some
things are buggy (eg subtract).
diff --git a/py/mpconfig.h b/py/mpconfig.h
index 00e2439..34c83d3 100644
--- a/py/mpconfig.h
+++ b/py/mpconfig.h
@@ -68,6 +68,7 @@
// Long int implementation
#define MICROPY_LONGINT_IMPL_NONE (0)
#define MICROPY_LONGINT_IMPL_LONGLONG (1)
+#define MICROPY_LONGINT_IMPL_MPZ (2)
#ifndef MICROPY_LONGINT_IMPL
#define MICROPY_LONGINT_IMPL (MICROPY_LONGINT_IMPL_NONE)