The new package subtle added in golang.org/cl/112236 breaks compatibility with App Engine due to the import of unsafe. This changes adds an App Engine alternative without using unsafe. Tested with: $ go test -test.tags=appengine -v === RUN TestAliasing --- PASS: TestAliasing (0.00s) PASS ok golang.org/x/crypto/internal/subtle 0.009s Change-Id: I2fc6b02a860b3ee11fa31652ba302fc7db9df153 Reviewed-on: https://go-review.googlesource.com/119095 Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org> Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org> TryBot-Result: Gobot Gobot <gobot@golang.org>