This enables support for hooks outside the database directory.
It relies strongly on configuration information being usable between
closing the database and destroying it.
Many of the external links found in the notmuch source can be resolved
using https instead of http. This changeset addresses as many as i
could find, without touching the e-mail corpus or expected outputs
found in tests.
Without this flush, if stdout is block buffered (which will happen if
it's a pipe or a file, for example) and the hook also writes to
stdout, then notmuch new's output will appear *after* the hook output.
This situation may be a little esoteric, but it's good practice to
flush before you fork anyway.
Add mechanism for running user defined hooks. Hooks are executables or
symlinks to executables stored under the new notmuch hooks directory,
<database-path>/.notmuch/hooks.
No hooks are introduced here, but adding support for a hook is now a simple
matter of calling the new notmuch_run_hook() function at an appropriate
location with the hook name.
Signed-off-by: Jani Nikula <jani@nikula.org>
