Added a new global __sglue object for all configurations.
Decouples the global file object list from the _GLOBAL_REENT
structure by using this new object instead of the __sglue member
of _GLOBAL_REENT in __sfp() and _fwalk_sglue().
Replaced _fwalk_reent() with _fwalk_sglue(). The change adds an
extra __sglue object as a parameter, which will allow the passing
of a global __sglue object separate from the __sglue member of
struct _reent. The global __sglue object will be added in a
follow-on patch.
This edits licenses held by Berkeley and NetBSD, both of which
have removed the advertising requirement from their licenses.
Signed-off-by: Keith Packard <keithp@keithp.com>