[Bug go/89447] libgo largefile support is incomplete and inconsistent

[ro at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=89447

--- Comment #1 from Rainer Orth <ro at gcc dot gnu.org> ---
Created attachment 45796
  --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=45796&action=edit
Initial patch