conflict from ocamlyacc?

[progman1]

ocamlyacc generates an mli with a fixed 'Lexing.lexbuf ...' and no way to
include anything extra, such as 'module Lexing=Sedlexing'.
so in my setup the compiler is seeing this as the Stdlib Lexing module,
while the generated .ml sees the header redirect and so the types are in conflict with
those of the .mli.

is there a well-known workaround for this (at least to me) surprising inconvenience?
I saw the ocamlyacc docs are explicit about this referring to the Stdlib module
so presumably there's a good reason for it.