Add some new APIs
V8 was updated to 7.8.279.23. This includes performance improvements to object
destructuring, RegExp match failures and WebAssembly startup time.

Signed-off-by: Hirokazu MORIKAWA <morikw2@gmail.com>

Update to v12.15.0
Support Python3 : https://github.com/openwrt/packages/issues/8893
Preparing to deprecate nosnapshot builds.

Signed-off-by: Hirokazu MORIKAWA <morikw2@gmail.com>

see: https://github.com/openwrt/packages/pull/8796

And remove uclibc depends

Signed-off-by: Hirokazu MORIKAWA <morikw2@gmail.com>