NAME:
	os_separator
 PURPOSE:
	Defines a couple of platform-dependent characters
 CATEGORY:
	environment
 CALLING SEQUENCE:
	char = os_separator( [/dir, /path] )
 OPTIONAL INPUT PARAMETERS:
	/dir			if set then the directory terminator is returned
	/path			if set then the path separator is returned
 OUTPUTS:
	char		scalar, type: char
					requested character (see above)
					/dir set : ] on vms, / on unix, \ on windows
					/path set: , on windows and vms, space on unix and mac
 INCLUDE:
	@compile_opt.pro			; On error, return to caller
 CALLS: ***
	InitVar
 CALLED BY:
	FindAllFiles, GetFileSpec, SetFileSpec, unhide_env, www_help_tree
 PROCEDURE:
	Checks !version.os_family to select platform.
 MODIFICATION HISTORY:
	JUN-2001, Paul Hick (UCSD/CASS; pphick@ucsd.edu)