Copyright (c) 1993 Xerox Corporation.  All rights reserved.
assert.h	replace DONE
ctype.h		okay for now, may eventually need per-thread locale?  bletch. 
errno.h		POSIX
float.h		okay ???
limits.h	POSIX
locale.h	NYI
math.h		okay
setjmp.h	POSIX
signal.h	POSIX
stdarg.h	okay
stddef.h	POSIX
stdio.h		replace eventually, but leave for now.
stdlib.h	replace (allocation procs, rand, )
string.h	should be okay. REPLACE for mem... fcns
time.h		POSIX.  This doesn't have everything -- I need to resolve this.