hg: openjfx/9-dev/rt: 8178075: Provide generic add-exports mechanism

[kevin.rushforth at oracle.com]

Changeset: 39925d9504e5
Author:    ddhill
Date:      2017-04-05 18:51 -0400
URL:       http://hg.openjdk.java.net/openjfx/9-dev/rt/rev/39925d9504e5

8178075: Provide generic add-exports mechanism
Reviewed-by: kcr, jgiles

! build.gradle
+ buildSrc/addExports