RFR: JDK-8217723 Switch ld from bfd to gold on gcc toolchain

[Martin Buchholz]

On Thu, Jan 24, 2019 at 7:46 AM Magnus Ihse Bursie
<magnus.ihse.bursie at oracle.com> wrote:

> So, we already tacitly assume a specific linker with the gcc toolchain; we have just not made that check explicitly.

gcc  runs on almost every system, but it's harder to replace the
compiler than the linker, so gcc ends up being used with many other OS
default linkers.
Same for clang.
Meanwhile, we have 3 competing open source linkers: bfd gold lld, so
linker availability is especially fluid these days.
Incremental linking will only be of interest to openjdk developers
(and then probably only hotspot developers) for non-release builds, so
should be opt-in.