hg: jdk9/sandbox: 8157623: Make --enable-ccache work properly with CCACHE from the environment

[chris.hegarty at oracle.com]

Changeset: c7258f229740
Author:    ihse
Date:      2016-10-12 11:49 +0200
URL:       http://hg.openjdk.java.net/jdk9/sandbox/rev/c7258f229740

8157623: Make --enable-ccache work properly with CCACHE from the environment
Reviewed-by: erikj

! common/autoconf/build-performance.m4
! common/autoconf/generated-configure.sh