python3 not detected, current master with python support is broken

Created by: jychoi-hpc

I am trying to build Adios2 with python3 but cmake detects as python2:

cmake -DPYTHON_EXECUTABLE=/usr/local/bin/python ..
-- The C compiler identification is GNU 7.4.0
-- The CXX compiler identification is GNU 7.4.0
-- Check for working C compiler: /usr/bin/cc
-- Check for working C compiler: /usr/bin/cc -- works
-- Detecting C compiler ABI info
-- Detecting C compiler ABI info - done
-- Detecting C compile features
-- Detecting C compile features - done
-- Check for working CXX compiler: /usr/bin/c++
-- Check for working CXX compiler: /usr/bin/c++ -- works
-- Detecting CXX compiler ABI info
-- Detecting CXX compiler ABI info - done
-- Detecting CXX compile features
-- Detecting CXX compile features - done
-- Could NOT find Blosc (missing: BLOSC_LIBRARY BLOSC_INCLUDE_DIR) (Required is at least version "1.7")
-- Found MPI_C: /usr/lib/x86_64-linux-gnu/openmpi/lib/libmpi.so (found version "3.1") 
-- Found MPI_CXX: /usr/lib/x86_64-linux-gnu/openmpi/lib/libmpi_cxx.so (found version "3.1") 
-- Found MPI: TRUE (found version "3.1") found components:  C CXX 
-- Could NOT find DataSpaces (missing: DATASPACES_VERSION DATASPACES_INCLUDE_DIR DATASPACES_LIBRARIES DSPACES_LIBRARY) (Required is at least version "1.8")
-- Found PythonInterp: /usr/local/bin/python (found version "2.7.17") 
-- Found PythonLibs: /usr/lib/x86_64-linux-gnu/libpython2.7.so (found suitable version "2.7.17", minimum required is "2.7.17") 
-- Found PythonModule_numpy: /usr/local/lib/python2.7/dist-packages/numpy  
-- Could NOT find PythonModule_mpi4py (missing: PythonModule_mpi4py_PATH) 
CMake Error at /usr/local/lib/python2.7/dist-packages/cmake/data/share/cmake-3.12/Modules/FindPackageHandleStandardArgs.cmake:137 (message):
  Could NOT find PythonFull (missing: mpi4py)
Call Stack (most recent call first):
  /usr/local/lib/python2.7/dist-packages/cmake/data/share/cmake-3.12/Modules/FindPackageHandleStandardArgs.cmake:378 (_FPHSA_FAILURE_MESSAGE)
  cmake/FindPythonFull.cmake:54 (find_package_handle_standard_args)
  cmake/DetectOptions.cmake:199 (find_package)
  CMakeLists.txt:133 (include)

I am sure that I provided python3:

/usr/local/bin/python --version
Python 3.6.9

I also installed numpy and mpi4py for python3:

/usr/local/bin/python -c "import numpy"
/usr/local/bin/python -c "import mpi4py"

There is no mpi4py installed for python2 (this is why I got an error message in the above, which make sense)

I will appreciate any help and advice.

Thanks.