Retrive 64bit timestamp from curl_easy_getinfo on _TIME_BITS=64 environment

Retrive 64bit timestamp from curl_easy_getinfo on _TIME_BITS=64 environment

On 32bit system compiled with -D_TIME_BITS=64, following tests failed:

FAIL: run-debuginfod-archive-test.sh
FAIL: run-debuginfod-archive-groom.sh
FAIL: run-debuginfod-archive-rename.sh
FAIL: run-debuginfod-federation-sqlite.sh
FAIL: run-debuginfod-federation-metrics.sh
FAIL: run-debuginfod-federation-link.sh

due to tests/debuginfod-subr.sh:archive_test failing on
"test $fileame -ot `pwd`", with LHS file having a bogus timestamp.
LHS is generated by debuginfo-find as a cache file.

I'm not sure the fix is the correct way, but
since -D_TIME_BITS=64 mandates -D_FILE_OFFSET_BITS=64 in glibc,
this does work on glibc environment.

Signed-off-by: Taketo Kabe <kabe@sra-tohoku.co.jp>