Replace the direct setting of variables for input and output variables
with accessors. This allows for properly tracking the lifetimes of the
data and allows for things like checking of the overwrite of the
primary input file to be centralized.
It isn't possible *in the general case* to check for overwrite of
*any* of the input files, although in the particularly important case
of the assembler proper it ought to be possible to do a bit better:
it should be able to guard for overwrites of non-primary input files
except for the error file or the list file if and only if -Lp is used.
That is, however, a latter project.
Signed-off-by: H. Peter Anvin (Intel) <hpa@zytor.com>
720a32672c