gpart-0.1h-alt7 on i586 fails to work with disks > 2 GiB:
*** Fatal error: dev(/dev/sdc): seek failure.
Seems that the patch to remove _llseek and subsequent large file support patches are completely broken.
Thanks for reporting and fixing this, and sorry for introducing the problem in the first place -- fortuntely haven't had the need for actual testing in a long time.
Fixed in 0.1h-alt8.
There are still more bugs in there - e.g., i586 and x86_64 versions behave differently on the same disk (on x86_64 the extended partition is not detected for some reason), but at least now the i586 version does not fail completely.