Add framework to support alternative implementations of long int Python type.
diff --git a/py/mpconfig.h b/py/mpconfig.h
index 6deb442..ada4aa2 100644
--- a/py/mpconfig.h
+++ b/py/mpconfig.h
@@ -62,6 +62,18 @@
#define MICROPY_ENABLE_LEXER_UNIX (0)
#endif
+// Long int implementation
+#define MICROPY_LONGINT_IMPL_NONE (0)
+#define MICROPY_LONGINT_IMPL_LONGLONG (1)
+
+#ifndef MICROPY_LONGINT_IMPL
+#define MICROPY_LONGINT_IMPL (MICROPY_LONGINT_IMPL_NONE)
+#endif
+
+#if MICROPY_LONGINT_IMPL == MICROPY_LONGINT_IMPL_LONGLONG
+typedef long long mp_longint_impl_t;
+#endif
+
// Whether to support float and complex types
#ifndef MICROPY_ENABLE_FLOAT
#define MICROPY_ENABLE_FLOAT (0)