py: Implement sys.maxsize, standard way to check platform "bitness".
Implementing it as a static constant is a bit peculiar and require cooperation
from long int implementation.
diff --git a/unix/mpconfigport.h b/unix/mpconfigport.h
index 002ea79..98132ac 100644
--- a/unix/mpconfigport.h
+++ b/unix/mpconfigport.h
@@ -45,6 +45,7 @@
#define MICROPY_PY_BUILTINS_FROZENSET (1)
#define MICROPY_PY_SYS_EXIT (1)
#define MICROPY_PY_SYS_PLATFORM "linux"
+#define MICROPY_PY_SYS_MAXSIZE (1)
#define MICROPY_PY_SYS_STDFILES (1)
#define MICROPY_PY_CMATH (1)
#define MICROPY_PY_IO_FILEIO (1)