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>
