hg: jdk8u/jdk8u-dev: 8203845: backport of JDK-8034788 inadvertently rolled back JDK-8187045 changes to toolchain.m4

[david.buck at oracle.com]

Changeset: d5dd14b37ea5
Author:    dbuck
Date:      2018-05-31 03:58 -0400
URL:       http://hg.openjdk.java.net/jdk8u/jdk8u-dev/rev/d5dd14b37ea5

8203845: backport of JDK-8034788 inadvertently rolled back JDK-8187045 changes to toolchain.m4
Summary: reapply JDK- 8187045 changes to flags.m4
Reviewed-by: tbell, erikj

! common/autoconf/flags.m4
! common/autoconf/generated-configure.sh