Add path to command to configurable options

[bugabinga]

This commit makes it a little bit more comfortable to add a custom script for use cases such as in #73.
When the variable is empty/undefined ldm simply prints The callback script isn't executable! but works fine.
I am unsure about the exact quoting rules in systemd service files.
Maybe the COMMAND_PATH should be wrapped in " in case of whitespace in path?

Tested this with following config:

/etc/ldm.conf

MOUNT_OWNER=oli
BASE_MOUNTPOINT=/home/oli/Mounts
FMASK_DMASK=0177,0077
COMMAND_PATH=/etc/ldm_notify.sh

/etc/ldm_notify.sh

#!/bin/sh
env DBUS_SESSION_BUS_ADDRESS=unix:path=/run/user/1000/bus /usr/bin/toastify send --icon mount --app-name ldm "$LDM_ACTION" "Mounted $LDM_NODE($LDM_FS) in $LDM_MOUNTPOINT."

[LemonBoy]

Thanks for the PR!

When the variable is empty/undefined ldm simply prints The callback script isn't executable! but works fine.

Oops, that's fixed now :)

I'd introduce an EXTRA_ARGS variable that's just appended after the usual options so that you can write EXTRA_ARGS=-c /my/path without having to worry too much about optional or missing arguments.

Don't forget to update the ldm.pod file too (GitHub kindly decided to stop rendering it, sigh)

[bugabinga]

EXTRA_ARGS is good idea.

Can you check, that the rendering of ldm.pod is okay?
I have never seen pod files before ;)

Btw, Github renders ldm.pod fine when you click it directly.
Only the symlink README.pod is broken.
Very weird.

[LemonBoy]

I have never seen pod files before ;)

It's a pretty nice format and with pod2man you can easily produce the man pages with no extra effort.

Can you check, that the rendering of ldm.pod is okay?

Github is nice enough to render the diff for you :)

Btw, Github renders ldm.pod fine when you click it directly.
Only the symlink README.pod is broken.
Very weird.

Such is technology, it used to work a couple of weeks ago :\