FIPS 140 service indicator revamp

[NIIBE Yutaka]

NIIBE Yutaka <gniibe at fsij.org> wrote:
> Here are ongoing changes:
>
> * Change 1: use of a new internal API for the FIPS service indicator.
>   Current proposal is using thread local storage, with compiler support
>   (__thread), to be conservative (not by modern C11 _Thread_local or C23
>   thread_local).
>
> * Change 2: new libgcrypt API for the FIPS service indicator (by macro
>   and gcry_control with new number), for applications.

These parts are pushed to master.

Also, for gcry_kdf_derive function, following was done.

> * Change 3: using the new internal API, modify libgcrypt; put
>   initialization (of false), put update (of true) in a success path, for
>   all relevant functions.
>
> * Change 4 (possibly, some parts would be optional): modify libgcrypt so
>   that it doesn't reject computation under FIPS mode for parameters, but
>   continue to finish the computation.  After this change, it won't
>   return an error for parameters issue (if it's not fatal), only setting
>   a failure with the FIPS service indicator.

It's tracked by:

   https://dev.gnupg.org/T7338

I'm going to try #3 and #4 for gcry_md_buffer function.
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