Node:Setting SP_PATH under Windows, Previous:Generic Runtime Systems, Up:Windows notes
The use of the SP_PATH variable under Windows is discouraged,
since Windows applications can find out for themselves where they were
started from.
SP_PATH is only used if the directory where sprt<ver>.dll
is loaded from does not contain sp<ver> (a directory) or
sprt.sav (where <ver> is "39" for SICStus version
3.9(.x)). If SP_PATH is used, SICStus expects it to be set such
that %SP_PATH%\bin contains sprt.sav. See Runtime Systems on Target Machines.