hg: build-infra/jdk9: Separate JVM_CFLAGS slightly to not avoid mixing together reasons for setting defines.

[magnus.ihse.bursie at oracle.com]

Changeset: 2e96b62db10c
Author:    ihse
Date:      2016-01-31 17:35 +0100
URL:       http://hg.openjdk.java.net/build-infra/jdk9/rev/2e96b62db10c

Separate JVM_CFLAGS slightly to not avoid mixing together reasons for setting defines.

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