matthieu, please don't replace the original xcombine_vol_data executable with the adios version here. based on your new file, rather just add a new executable xcombine_vol_data_adios when ADIOS is supported, so users will have the choice between the two xcombine_vol_data*** executables in case. 

even better - but only if you like to continue work on it - you could try to merge these two source files to avoid code redundancy and check for the ADIOS_ENABLED parameter in the Par_file to determine if you use the adios routines or not, i.e., making it run-time rather than compile-time dependent...