[Libguestfs] [PATCH 0/4] qemu: Use sqlite to store qemu detection data.

Patches 1 & 2 were posted previously here: https://www.redhat.com/archives/libguestfs/2016-May/msg00134.html Patch 3 is a hack so I can test this using my own version of qemu (the `-L ?' stuff is not upstream). Patch 4 is where the real action takes place: Replace the caching of qemu features in blob-like files with a sqlite database. Probably the best way to approach this patch is to start with the schema (src/qemu-schema.sql) and the sqlite C API documentation (https://www.sqlite.org/cintro.html). Rich.