Move FSMonitor config settings to a new `struct fsmonitor_settings`
structure. Add a lazily-loaded pointer to `struct repo_settings`.
Create `fsm_settings__get_*()` getters to lazily look up fsmonitor-
related config settings.
Get rid of the `core_fsmonitor` global variable, and add support for
the new `core.useBuiltinFSMonitor` config setting. Move config code
to lookup the existing `core.fsmonitor` value to `fsmonitor-settings.[ch]`.
The `core_fsmonitor` global variable was used to store the pathname to
the FSMonitor hook and it was used as a boolean to see if FSMonitor
was enabled. This dual usage will lead to confusion when we add
support for a builtin FSMonitor based on IPC, since the builtin
FSMonitor doesn't need the hook pathname.
Replace the boolean usage with an `enum fsmonitor_mode` to represent
the state of FSMonitor. And only set the pathname when in HOOK mode.
Signed-off-by: Jeff Hostetler <jeffhost@microsoft.com>
81f7337e3d