A couple of things. First, I have in mind something different for _GL_ATTRIBUTE_NORETURN, since _Noreturn is in draft C1X. I'll send out some proposed patches for this shortly.
Second, don't you need to do something different for the *.in.h files, such as lib/string.in.h? They can't include gnulib's .h files, which is why they have that complicated build procedure.
