_cleanup() vs Linux fcloseall()

[Daniel Eischen]

It seems that some 3rd party code, pmake in particular, rely on
the implementation exporting _cleanup() to close all open file
descriptors.  Linux supplies fcloseall() and does not export
_cleanup().

In the initial cut of symbol versioning for libc, I did not
export _cleanup().  This breaks pmake, and perhaps some other
3rd party applications.  Do we want to continue to export this
interface, or should we provide an equivalent of Linux'
fcloseall()?

-- 
DE