#ifdef USE_64_BIT_STDIO
....
#   if defined(USE_FGETPOS64)
#       define fgetpos fgetpos64
#   endif

and

#ifdef USE_64_BIT_STDIO
#   ifdef HAS_FPOS64_T
#       undef Fpos_t
#       define Fpos_t fpos64_t
#   endif

yet in config_H.vc contains
#define Fpos_t fpos_t		/* File position type */