Buildroot: HDF5 configure error when using --enable-parallel with MPICH

Hello,

I am trying to compile HDF5 for embedded ARM using buildroot and I found
this patch https://patchwork.ozlabs.org/patch/425217/ .

I am actually new to buildroot and cross compiling and had many
difficulties with configuring HDF5, then the patch helped me to set all
the AC_TRY_RUN variables and everything worked perfectly.

To extend my work, I needed to install the mpich library to run HDF5 in
parallel mode. MPICH was installed correctly, then I just added the
--enable-parallel flag to my HDF5 configuration and then a new error
messages occured at the configuration:

checking whether a simple MPI-IO program can be linked... no
configure: error: unable to link a simple MPI-IO application

I wanted to deactivate this test but I couldn't find which variable to
set.
This is the part of code responsible for the test in configure.ac:

  ## Check that we can link a simple MPI and MPI-IO application
  AC_MSG_CHECKING([whether a simple MPI-IO program can be linked])
  AC_TRY_LINK(, [MPI_Init(); MPI_File_open();],
              [AC_MSG_RESULT([yes])],
              [AC_MSG_RESULT([no])
              AC_MSG_ERROR([unable to link a simple MPI-IO application])])

I couldn't figure out how to influence the result of this test.

May be someone has an idea how to install HDF5 with --enable-parallel
using buildroot?

Thanks,

Mehdi