WIP: Introduce flag to control enforcement of Fermi hole curvature
Tentative fix to #427
Changes the logic from compile-time to run-time. The flag can be turned on or off at runtime by func->info->flags = func->info->flags | XC_FLAGS_ENFORCE_FHC;
and func->info->flags = func->info->flags ^ XC_FLAGS_ENFORCE_FHC;
, respectively. A single version of the library can be used with either type of code.
TBD: we will need a new function in Fortran: xc_f03_func_info_set_flags(info, flags)
and a corresponding xc_func_info_get_flags(*info, flags)