Originally, libyt can only be compiled by mpic++, and run with mpirun -np 1 in serial mode.
This PR removes the dependency when running in serial mode.
Add -DSERIAL_MODE option. This uses g++ to compile libyt, if we want it to run in serial.
Update GitHub Action to be able to test libyt installation via g++.
Support Serial Mode using GCC Compiler
Originally,
libytcan only be compiled bympic++, and run withmpirun -np 1in serial mode. This PR removes the dependency when running in serial mode.-DSERIAL_MODEoption. This usesg++to compilelibyt, if we want it to run in serial.g++.