[Libguestfs] [PATCH nbdkit v3 0/6] plugins: Implement magic config key.

v1: https://www.redhat.com/archives/libguestfs/2018-September/msg00024.html v2: https://www.redhat.com/archives/libguestfs/2018-September/msg00034.html v3: - Fixed is_config_key zero length test. - Fixed is_config_key so it uses strspn and is not O(n^2). - Changed >= 1.7 to >= 1.8 in the documentation. Rich.