hg: bsd-port/jdk8/hotspot: Disable some warnings for clang6 that prevent the build from completing.

[kurt at intricatesoftware.com]

Changeset: 8893a58dd2d7
Author:    Kurt Miller <kurt at intricatesoftware.com>
Date:      2018-04-17 19:32 -0400
URL:       http://hg.openjdk.java.net/bsd-port/jdk8/hotspot/rev/8893a58dd2d7

Disable some warnings for clang6 that prevent the build from completing.

! make/bsd/makefiles/gcc.make