[Libguestfs] [PATCH v3 0/5] threads: Add support for thread-safe handle.

Previously posted in 2015: v1: https://www.redhat.com/archives/libguestfs/2015-June/msg00048.html v2: https://www.redhat.com/archives/libguestfs/2015-June/msg00118.html I have rebased and tidied up the patches, fixing a few spelling mistakes, but they are broadly the same as before. I also ran all the tests, which pass. As with the previous versions, this makes a change to the API, where you can no longer pass a handle between threads and expect guestfs_last_error() to work. I'm somewhat more sanguine about this change, since using the API like that is abstruse and no one should be expecting that to have worked. Rich.