Use the <iostream> C++ header

Source: http://www.mario-konrad.ch/wiki/doku.php?id=programming:flexbison:flexppbisonpp
Remove obsolete <osfcn.h>
Remove an unnecessary GCC workaround
Replace bzero with memset
Remove unnecessary <strings.h>
Use prototypes from <unistd.h>
Always include <string.h>
Remove a workaround for !__STDC__
Remove more unnecessary GCC workarounds
Remove trailing whitespace
Fix a typo
Constify pointers to static strings
Don't redefine const

It's 2014.  Everyone should support const by now.
Remove support for old-style function prototypes

It's 2014.  Everyone should support new-style prototypes by now.
This also removes a bunch of clutter.
Remove RCS ID strings
Avoid emitting trailing whitespace
Regenerate scan.c