Installing a generated header file

[Bill Schmidt]

Hi!  I'm working on a project where it's desirable to generate a target-specific header
file while building GCC, and install it with the rest of the target-specific headers
(i.e., in lib/gcc/<target>/11.0.0/include).  Today it appears that only those headers
listed in "extra_headers" in config.gcc will be placed there, and those are assumed to
be found in gcc/config/<target>.  In my case, the header file will end up in my build
directory instead.

Questions:

* Has anyone tried something like this before?  I didn't find anything.
* If so, can you please point me to an example?
* Otherwise, I'd be interested in advice about providing new infrastructure to support
   this.  I'm a relative noob with respect to the configury code, and I'm sure my
   initial instincts will be wrong. :)

Thanks for any help!

Bill