When processing integers to/from pointers, we would like to have an integer type which has the same size as a pointer. Currently, it's always the case for [s]size_t but it's preferable to have a specific type which will always offer this guarantee, like [u]intptr_t. Fix this lazily by defining [u]intptr_ctype to [s]size_t_ctype. Note: this intptr_t is just internal to sparse and can be different from the type choosen by the libc/platform. Signed-off-by: Luc Van Oostenryck <luc.vanoostenryck@gmail.com>