utils: build sha1/disk cache only with Android/Autoconf

Earlier commit imported a SHA1 implementation and relaxed the SHA1 and
disk cache handling, broking the Windows builds.

Restrict things for now until we get to a proper fix.

Fixes: d1efa09d342 "util: import sha1 implementation from OpenBSD"
Signed-off-by: Emil Velikov <emil.velikov@collabora.com>
6 files changed