Use intptr_t in C when talking about a pointer.

This fixes a bug in TS where we'd return an int64_t when we intended
to return a pointer, confusing JavaScript as to why it has a bigint
instead of a number.

This may make it harder to support 32-bit Java platforms in the
future if we have a reason to do so, but that seems unlikely and
its possible we can simply redefine the type.

Author: TheBlueMatt

genbindings.py

@@ -288,7 +288,7 @@ def java_c_types(fn_arg, ret_arr_len):
             fn_arg = fn_arg[8:].strip()
         else:
             java_ty = consts.ptr_native_ty
-            c_ty = "int64_t"
+            c_ty = "intptr_t"
             arr_ty = "uintptr_t"
             rust_obj = "uintptr_t"
             fn_arg = fn_arg[9:].strip()