* harbour/source/rtl/diskspac.c
* harbour/source/rtl/disksphb.c
* use statvfs() instead of statfs() in *nixes - unlike statfs()
statvfs() is documented POSIX function
* respect superuser status in calculating free space in DISKSPACE()
* respect _SET_FILECASE, _SET_DIRCASE in HB_DISKSPACE()
* accept numeric parameter with driver number in systems
which supports drive letters
* harbour/source/rtl/binnum.c
* harbour/source/rtl/binnumx.c
* force positive return value in BIN2W() and BIN2U()
