hg: jdk8u/jdk8u: 8151841: Build needs additional flags to compile with GCC 6 [plus parts of 8149647 & 8032045]

[rob.mckenna at oracle.com]

Changeset: 73494e6ff8e5
Author:    andrew
Date:      2016-07-11 05:02 +0100
URL:       http://hg.openjdk.java.net/jdk8u/jdk8u/rev/73494e6ff8e5

8151841: Build needs additional flags to compile with GCC 6 [plus parts of 8149647 & 8032045]
Summary: C++ standard needs to be explicitly set and some optimisations turned off to build on GCC 6
Reviewed-by: erikj, dholmes, kbarrett

! common/autoconf/generated-configure.sh
! common/autoconf/hotspot-spec.gmk.in
! common/autoconf/spec.gmk.in
! common/autoconf/toolchain.m4