[committed] libstdc++: Move "free books" list from fsf.org to gnu.org

[Jonathan Wakely]

On 01/04/20 22:47 +0200, Gerald Pfeifer wrote:
>The fsf.org server now has a redirect to the gnu.org server; let's
>follow that.
>
>This is my first commit to libstdc++ using git, my first squashing
>(since I had a follow tweak to the ChangeLog), and my first --amend.
>
>Please advise if I can/should do something better.

Looks fine - thanks!