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()