Changing the way we bootstrap openjdk ports

Hi,

I've submitted a patch for java/openjdk24 that change how it obtains the
bootstrap jdk needed to build the port:

https://reviews.freebsd.org/D50349

Traditionally the openjdk ports will add the previous version of the jdk
as a dependency if a suitable jdk for building the current version is
not already installed on the system. For some specific versions it will
add the most suitable java/bootstrap-openjdk version instead.

This means that to build one of the later OpenJDK versions from ports,
the system may end up building and installing a number of the previous
versions as well, as it walks down the dependency path until it finds a
bootstrap-openjdk dependency.

The proposed change will instead download a suitable prebuilt openjdk
from the freebsd distcache servers and extract it to the ${WRKSRC}
directory before running configure for the port. This makes the prebuilt
jdk available to the port during build, but does not install it to the
system.

The idea is to make such prebuilt jdk's that can be used as bootstrap
jdk's for all relevant versions, and change all the openjdk ports to use
the same mechanism.

This should save both time and installed size when building one of the
openjdk ports.

Any feedback, or objections to this scheme is most welcome!


Tale Care!
--
Harald