base: use uintptr_t for hash type

Use uintptr_t for hash type; this is consistent with CoreFoundation, which uses
32-bit integers on 32-bit platforms for the hash code, and 64-bit integers on
64-bit platforms. (libheimbase is modelled on CoreFoundation.)

Previously we used unsigned long, which would have the same behavior on
LP32/LP64 systems, but not on Windows (where unsigned long is 32-bits on 64-bit
platforms).

lib/base/number.c

@@ -58,12 +58,12 @@ number_cmp(void *a, void *b)
     return na - nb;
 }
 
-static unsigned long
+static uintptr_t
 number_hash(void *ptr)
 {
     if (heim_base_is_tagged_object(ptr))
 	return heim_base_tagged_object_value(ptr);
-    return (unsigned long)*(int *)ptr;
+    return (uintptr_t)*(int64_t *)ptr;
 }
 
 struct heim_type_data _heim_number_object = {