This updates OpenJDK 8 to a newer version and brings a bunch of
changes.
Newly, it is bootstrapped with openjdk7-bootstrap, so it does not
need to download binaries. It can also cross-compile and is patched
for musl and other platforms.
We're newly using the aarch64 port repo in order to get aarch64
JIT. For non-aarch64 platforms, the codebase is the same.
The symlink for /usr/lib/jvm/openjdk is also now gone and we're
using a unified java-VERSION-VENDOR naming.
Also general template cleanup.
[ci skip]
The `etc/virtual` file declares the default package to be built for
virtual dependencies declared as "virtual?foo" in $depends.
Before this change, the run-time dependency was added as is to the final
binary package but no pkg providing this virtual pkg was built.
With this file we declare the *default* pkg to be built.
NOTE: "virtual?foo" is only applicable to *run* time dependencies, i.e
only those declared in $depends.
The `etc/defaults.virtual` file contains the default replacement
for our use cases; at this moment we only use it to use `eudev`
rather than `systemd` for udev.
If `etc/virtual` exists it overrides the settings of `etc/defaults.virtual`.
