Move auxiliary build scripts into separate directory.
Move auxiliary build scripts into separate directory.

* configure.ac: Move auxiliary build scripts into separate directory
`build-aux'.

Signed-off-by: Justus Winter <4d1bd7a5ca1cd26bee0df05b6801a6ce9a22196e@g10code.com>

gpg/scute,gpg/scute,gpg/scute