Re: Fix deprecated utcnow() usage in build-many-glibcs.py

[Florian Weimer <fweimer@redhat.com>]

* Joseph Myers:

> Running build-many-glibcs.py with Python 3.12 or later produces a
> warning:
>
> build-many-glibcs.py:566: DeprecationWarning: datetime.datetime.utcnow() is deprecated and scheduled for removal in a future version. Use timezone-aware objects to represent datetimes in UTC: datetime.datetime.now(datetime.UTC).
>   build_time = datetime.datetime.utcnow()
>
> Replace with datetime.datetime.now(datetime.timezone.utc) (the
> datetime.UTC constant is new in 3.11, so not suitable for use in this
> script at present).
>
> diff --git a/scripts/build-many-glibcs.py b/scripts/build-many-glibcs.py
> index 7e0b90be89..87a42e4aef 100755
> --- a/scripts/build-many-glibcs.py
> +++ b/scripts/build-many-glibcs.py
> @@ -563,7 +563,7 @@ class Context(object):
>                  print(config.name, config.compiler.name)
>              return
>          self.clear_last_build_state(action)
> -        build_time = datetime.datetime.utcnow()
> +        build_time = datetime.datetime.now(datetime.timezone.utc)
>          if action == 'host-libraries':
>              build_components = ('gmp', 'mpfr', 'mpc')
>              old_components = ()

Double-checked that this works with Python 3.6, looks good, thanks.

Florian