hg: jdk9/sandbox: 2 new changesets

[magnus.ihse.bursie at oracle.com]

Changeset: 452419b006ef
Author:    ihse
Date:      2017-06-20 23:48 +0200
URL:       http://hg.openjdk.java.net/jdk9/sandbox/rev/452419b006ef

Lots of changes...

! common/doc/building.html
! common/doc/building.md

Changeset: ab2ffe5a87b7
Author:    ihse
Date:      2017-06-21 00:38 +0200
URL:       http://hg.openjdk.java.net/jdk9/sandbox/rev/ab2ffe5a87b7

Make and Performance sections finished.
Update help text in Init.gmk.

! common/doc/building.html
! common/doc/building.md
! make/Init.gmk