Surprising. I thought it’s a purely kodi thing.
For a regular keyboard, there is no problem. But remotes are handled quite differently in libreelec and osmc. At least the one I’m currently using 
Shouldn’t be – we both use eventlircd and lircd.
They do use a different keyboard.xml though – but that can just be copied over, or you can use Keymap Editor in OSMC or record your own profile.
There is work ongoing for x86, but it takes time.
eventlircd does not seem to be involved here at all. I can kill the eventlircd demon and the remote will just continue to work. The remote comes with its own USB receiver, so it seems to be handled by some other subsystem. Which I’m still trying to understand. The differences in the keyboard.xml files are not that big.
It will be handled by the kernel then unless you set up an LIRC keymap. LE probably disable LIRC out of the box now.
You can either use an LIRC profile or ir-keytable. The built in receiver will be in LIRC mode (Bridge) but external would likely be loading the RC6 decoder. Both can be configured
I looked at this again to remember a couple of things.
The advice here should help you out: IR remote key mapping [SOLVED] - #2 by Dilligaf.
Sam