update docs

doc/sphinx/src/building.rst

@@ -21,6 +21,7 @@ General list of cmake options:
 || PARTHENON\_ENABLE\_ASCENT                || OFF                           || Option || Enable Ascent for in situ visualization and analysis                                                                                                        |
 || PARTHENON\_DISABLE\_MPI                  || OFF                           || Option || MPI is enabled by default if found, set this to True to disable MPI                                                                                         |
 || PARTHENON\_ENABLE\_HOST\_COMM\_BUFFERS   || OFF                           || Option || MPI communication buffers are by default allocated on the execution device. This options forces allocation in memory accessible directly by the host.       |
+|| PARTHENON\_ENABLE\_SERIAL\_POOL          || OFF                           || Option || The parthenon tasking infrastructure is multi-threaded by default. This option disables the multi-threading in the tasking, but not in individual tasks.    |
 || PARTHENON\_DISABLE\_SPARSE               || OFF                           || Option || Disable sparse allocation of sparse variables, i.e., sparse variable still work but are always allocated. See also :ref:`sparse doc <sparse compile-time>`. |
 || ENABLE\_COMPILER\_WARNINGS               || OFF                           || Option || Enable compiler warnings                                                                                                                                    |
 || TEST\_ERROR\_CHECKING                    || OFF                           || Option || Enables the error checking unit test. This test will FAIL                                                                                                   |