How to write directly to config.h from configure?

[Jeffrey Walton]

Hi Everyone,

I have a bad interaction with a project and Autotools. The project is
not an Autotools project but we are trying to [cleanly] support
Autotools. The project provides its own config.h since the mid-1990's.
We want to supply roughly the same file though Autotools.

The problem is, the project's config.h has some stuff that does not
seem to fit in the Autotools model like typedefs and declarations of
namespaces. I think the solution is to write directly to config.h but
I can't figure out how to do it. Testing code like below is lost
(i.e., it is not in the resulting config.h):

    ## Some real autoconf tests...

    cat << EOT >> config.h
      typedef unsigned char byte;
      typedef unsigned short word16;
      typedef unsigned int word32;
    EOT

    ## Back to real autoconf tests...

Is it possible to write directly to config.h? If yes, then how do I do it?

Jeff