hg: jdk9/sandbox: 8151841: Build needs additional flags to compile with GCC 6

[chris.hegarty at oracle.com]

Changeset: 9d77f922d694
Author:    andrew
Date:      2016-03-19 01:28 +0000
URL:       http://hg.openjdk.java.net/jdk9/sandbox/rev/9d77f922d694

8151841: Build needs additional flags to compile with GCC 6
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/flags.m4
! common/autoconf/generated-configure.sh
! common/autoconf/hotspot-spec.gmk.in
! common/autoconf/spec.gmk.in
! common/autoconf/toolchain.m4