Re: [PATCH v2 6/6] commit-graph: add repo arg to graph readers

>> 32-bit builds complain about this:
>>
>>   t/helper/test-repository.c: In function 'test_parse_commit_in_graph':
>>   t/helper/test-repository.c:28:9: error: format '%lu' expects argument of type 'long unsigned int', but argument 2 has type 'timestamp_t {aka long long unsigned int}' [-Werror=format=]
>>     printf("%lu", c->date);
>>          ^
>>   cc1: all warnings being treated as errors
>>   Makefile:2262: recipe for target 't/helper/test-repository.o' failed
>>   make: *** [t/helper/test-repository.o] Error 1
>
> Let's also state how we usually fix this:
>
>         printf("%"PRItime, c->date);