Deprecation question - is proposed code-change back-portable to V1.8.7?

[Ian Hulin <ian@hulin.org.uk>]

Hi all,
In working with Guile V2.0.6, compiling the following code gives
deprecation errors for both scm_sym2var and scm_module_lookup_closure.

From looking at the docs following the recommendations in the
deprecation messages, it looks like the offending line needs to change to
  return scm_module_variable ( module, sym);

Does scm_module_variable internally do what scm_module_lookup_closure
did, and if so, does Guile 1.8.7 do exactly the same as Guile 2.06?

Asking hear as we're getting near to a release and I don't want to
break anything bigtime on the LilyPond repo.

Cheers,
Ian Hulin

/* Lookup SYM, but don't give error when it is not defined.  */
SCM
ly_module_lookup (SCM module, SCM sym)
{
#define FUNC_NAME __FUNCTION__
  SCM_VALIDATE_MODULE (1, module);

  return scm_sym2var (sym, scm_module_lookup_closure (module),
SCM_BOOL_F);
#undef FUNC_NAME
}