[PATCH 06/19] Define IN_MODULE for translation units that define NOT_IN_libc

[Roland McGrath]

> Those symbols are not exported outside libc.so, thus resulting in a
> linker error in every DSO we build, except libc.so.

Oh, I see.  I'd forgotten we were using interp.c for any other libraries.
I think nowadays we actually should not be, because none of the others has
an entry point set that actually works (alas, dlfcn/eval.c is long defunct).
So let's just fix that first.