py: Correctly set sys.maxsize value for 64-bit.

Type representing signed size doesn't have to be int, so use special value
which defaults to SSIZE_MAX, but as it's not defined by C standard (but rather
by POSIX), allow ports to set it.

py/mpconfig.h

@@ -448,6 +448,10 @@ typedef double mp_float_t;
 #define MP_PLAT_FREE_EXEC(ptr, size) m_del(byte, ptr, size)
 #endif
 
+#ifndef MP_SSIZE_MAX
+#define MP_SSIZE_MAX SSIZE_MAX
+#endif
+
 // printf format spec to use for mp_int_t and friends
 #ifndef INT_FMT
 #ifdef __LP64__

py/objint_longlong.c

@@ -52,7 +52,7 @@
 
 #if MICROPY_PY_SYS_MAXSIZE
 // Export value for sys.maxsize
-const mp_obj_int_t mp_maxsize_obj = {{&mp_type_int}, INT_MAX};
+const mp_obj_int_t mp_maxsize_obj = {{&mp_type_int}, MP_SSIZE_MAX};
 #endif
 
 mp_int_t mp_obj_int_hash(mp_obj_t self_in) {

py/objint_mpz.c

@@ -47,14 +47,14 @@
 // Export value for sys.maxsize
 #define DIG_MASK ((1L << MPZ_DIG_SIZE) - 1)
 STATIC const mpz_dig_t maxsize_dig[MPZ_NUM_DIG_FOR_INT] = {
-    (INT_MAX >> MPZ_DIG_SIZE * 0) & DIG_MASK,
-    #if (INT_MAX >> MPZ_DIG_SIZE * 0) > DIG_MASK
-    (INT_MAX >> MPZ_DIG_SIZE * 1) & DIG_MASK,
-    #if (INT_MAX >> MPZ_DIG_SIZE * 1) > DIG_MASK
-    (INT_MAX >> MPZ_DIG_SIZE * 2) & DIG_MASK,
-    (INT_MAX >> MPZ_DIG_SIZE * 3) & DIG_MASK,
-    (INT_MAX >> MPZ_DIG_SIZE * 4) & DIG_MASK,
-//    (INT_MAX >> MPZ_DIG_SIZE * 5) & DIG_MASK,
+    (MP_SSIZE_MAX >> MPZ_DIG_SIZE * 0) & DIG_MASK,
+    #if (MP_SSIZE_MAX >> MPZ_DIG_SIZE * 0) > DIG_MASK
+    (MP_SSIZE_MAX >> MPZ_DIG_SIZE * 1) & DIG_MASK,
+    #if (MP_SSIZE_MAX >> MPZ_DIG_SIZE * 1) > DIG_MASK
+    (MP_SSIZE_MAX >> MPZ_DIG_SIZE * 2) & DIG_MASK,
+    (MP_SSIZE_MAX >> MPZ_DIG_SIZE * 3) & DIG_MASK,
+    (MP_SSIZE_MAX >> MPZ_DIG_SIZE * 4) & DIG_MASK,
+//    (MP_SSIZE_MAX >> MPZ_DIG_SIZE * 5) & DIG_MASK,
     #endif
     #endif
 };