hg: build-infra/jdk7: Guarding RC_FLAGS with ifndef to prevent it from overwriting additions to it in legacy makefiles (where spec is loaded multiple times).

[erik.joelsson at oracle.com]

Changeset: 7059bcf6b027
Author:    erikj
Date:      2011-11-04 15:01 +0100
URL:       http://hg.openjdk.java.net/build-infra/jdk7/rev/7059bcf6b027

Guarding RC_FLAGS with ifndef to prevent it from overwriting additions to it in legacy makefiles (where spec is loaded multiple times).

! common/config/spec.gmk.in