Include _caml_mirage_iopage_{alloc_pages,get_addr}

Fixes the recent CI error. Caused by stubs moving from one .a to
another in an upstream dependency.

Signed-off-by: David Scott <dave@recoil.org>

Author: djs55

Makefile

@@ -115,6 +115,7 @@ OCAML_LDLIBS := -L $(OCAML_WHERE) \
 	$(shell ocamlfind query cstruct)/cstruct.a \
 	$(shell ocamlfind query cstruct)/libcstruct_stubs.a \
 	$(shell ocamlfind query io-page)/io_page.a \
+	$(shell ocamlfind query io-page)/libio_page_stubs.a \
 	$(shell ocamlfind query io-page-unix)/io_page_unix.a \
 	$(shell ocamlfind query io-page-unix)/libio_page_unix_stubs.a \
 	$(shell ocamlfind query lwt.unix)/liblwt_unix_stubs.a \