What version of the game?
Steam and Uplay = Rename \FarCry5\bin\EasyAntiCheat\EasyAntiCheat_x64.dll and use the newest ~15 kb or so file from the first post in it's place. Also might want to rename \FarCry5\Bin\EACLaunch.exe
Leave everything else as is, don't do anything with FC_m64.dll it's no longer required.
Other version such as Codex? Apparently these already have workarounds for EAC so don't use these files, differences in the exe or the fc_m64.dll might render some options incompatible but L0wbit above has a table tailored for this version of the game so that should work.
EDIT: So far there's a patch in testing but there's been no more updates since 1.2.0 -> 1.4.0 from earlier.
EDIT: My bad, two threads. Use the .dll from the *other* Far Cry 5 thread about the EAC workaround and engine discussion from the first post.
EDIT: Which is gone, since the forum software was reverted and that took out a few tables and other posted or attached content as a result.
viewtopic.php?f=4&t=6334
EDIT:
Temporary, until the missing files and such can be restored.