w32: Require --enable-build-timestamp for the BUILD_HOSTNAME.
* configure.ac (BUILD_HOSTNAME): Set to "<anon>" bey default. * build-aux/speedo.mk (speedo_pkg_gnupg_configure): Add --enable-build-timestamp.
- Debian-bug-id: #826309
- Signed-off-by: Werner Koch <wk@gnupg.org>