hg: jdk9/sandbox: * Improve comments.

[magnus.ihse.bursie at oracle.com]

Changeset: 3cae11f13c11
Author:    ihse
Date:      2015-03-25 11:41 +0100
URL:       http://hg.openjdk.java.net/jdk9/sandbox/rev/3cae11f13c11

* Improve comments.
* Move BUILD_LOG stuff away from spec.gmk into Init
* Improve detection of make -j.

! common/autoconf/basics.m4
! common/autoconf/configure.ac
! common/autoconf/generated-configure.sh
! common/autoconf/spec.gmk.in
! make/Init.gmk
! make/InitSupport.gmk
! make/Main.gmk
! make/MainSupport.gmk