V8 cannot be built for iOS nor for Android

[ubamrein]

In the blog post of the 5.0 announcement you say, android and iOS support the v8 backend. Sadly it seems to build neither on Android nor on iOS due to missing source-tar balls of the custom wee-8 images. If it is really a build issue I cannot tell, as we did not further follow down that path but tried getting wasmi/wamr to build for iOS.

Nevertheless, the problematic line can be found in the build.rs file, where for all android/iOS targets no source can be found.

[syrusakbary]

Good point! We didn't enabled it because we haven't tested it, but I believe should be easy to enable v8 in iOS an Android. @xdoardo can probably take a look on this in the next week or so