R_ParseVector API change

Dear R developers,

just a quick question: I noted that R_ParseVector () has gained an additional 
parameter (since SVN rev. 39999). Since R_ParseVector () is part of the 
public API, I'm wondering, whether this API change was intentional or not. 
Either way is fine with me, but in order to make sure the next release of 
RKWard will be compilable with R 2.5.0, I'd like to make sure, whether or not 
the change is here to stay.

The change was accidental (I forgot that R_ParseVector was in the API 
when I made it), but I think it will stay.  Setting the value of this 
parameter to R_NilValue gets the old behaviour.  Setting it to some 
other SEXP will have that SEXP recorded as the srcfile attribute of 
source references.

I think the description above is the level of detail of the 
implementation that it's safe to work with.  The particular format of 
source references could change.

Duncan Murdoch