Unable to build ReLM

[ts2021]

I am unable to build ReLM. I am using ubuntu, gcc version 7.5.0, python 3.8.12. Build is failing with OpenFST; error is below

 extensions/_pywrapfst.cpp:1254:10: fatal error: fst/util.h: No such file or directory
   #include <fst/util.h>
            ^~~~~~~~~~~~
  compilation terminated.
  error: command '/usr/bin/gcc' failed with exit code 1
  [end of output]

note: This error originates from a subprocess, and is likely not a problem with pip.
ERROR: Failed building wheel for pynini

[eylkc]

Did you install OpenFST in a non-default prefix? If so, you will have to change the setup.py and and '-I/your/directory/openfst/include' to the extra_compile_args.