add option to update cache in a background process

the cli flag is undocumented for now, since it's experimental.

Closes: https://codeberg.org/nsxiv/nsxiv/issues/416
Closes: https://codeberg.org/nsxiv/nsxiv/pulls/425
Co-authored-by: explosion-mental <explosion0mental@gmail.com>

1 files changed, 1 insertions, 0 deletions

diff --git a/nsxiv.h b/nsxiv.h
index e137bfe..3ffc113 100644
--- a/nsxiv.h
+++ b/nsxiv.h
@@ -274,6 +274,7 @@ struct opt {
 	bool thumb_mode;
 	bool clean_cache;
 	bool private_mode;
+	bool background_cache;
 };
 
 extern const opt_t *options;