Close backends prior to shutdown

We need some way to signal the backends that we are about to shutdown,
allowing them to clean up (for example in notmuch committing the db changes).
This commit implements a hook which gets called upon shutdown, providing
backends implement the io.Closer interface.

1 files changed, 1 insertions, 0 deletions

diff --git a/aerc.go b/aerc.go
index c71c384..c5d93ac 100644
--- a/aerc.go
+++ b/aerc.go
@@ -178,4 +178,5 @@ func main() {
 			time.Sleep(16 * time.Millisecond)
 		}
 	}
+	aerc.CloseBackends()
 }