NAME
    SetProgramDir -- Sets the directory returned by getprogramdir (v36)
SYNOPSIS
    oldlock = SetProgramDir(lock)
    D0                       D1
    BPTR SetProgramDir(BPTR)
FUNCTION
    Sets a shared lock on the directory the program was loaded from.
    This can be used for a program to find data files, etc, that are
    stored with the program, or to find the program file itself.  NULL
    is a valid input.  This can be accessed via getprogramdir() or
    by using paths relative to PROGDIR:.
INPUTS
    lock - A lock on the directory the current program was loaded from
RESULT
    oldlock - The previous ProgramDir.
SEE ALSO
    getprogramdir(), open()