Possibility to opt at compile time for a XML reading made only by IO node and then broadcast the result
Introduces the possibility to choose at compile whether only ionode has to read the xml data file.
To activate this modality one has to define manually the flag -D__BEOWULF to MANUAL_DFLAGS in make.inc file.
to broadcast the data we use the bcast_qes_module.f90 file taken from thermo_pw sources.
It can be useful when running in environments without a parallel filesystem.