Add eclipse.ini changes in README.md

See google#991

Author: pbaumard

README.md

@@ -72,6 +72,17 @@ Drop it into the Eclipse
 [drop-ins folder](http://help.eclipse.org/neon/index.jsp?topic=%2Forg.eclipse.platform.doc.isv%2Freference%2Fmisc%2Fp2_dropins_format.html)
 to activate the plugin.
 
+Paste also these lines to the `eclipse.ini` file:
+
+```
+--add-exports=jdk.compiler/com.sun.tools.javac.api=ALL-UNNAMED
+--add-exports=jdk.compiler/com.sun.tools.javac.code=ALL-UNNAMED
+--add-exports=jdk.compiler/com.sun.tools.javac.file=ALL-UNNAMED
+--add-exports=jdk.compiler/com.sun.tools.javac.parser=ALL-UNNAMED
+--add-exports=jdk.compiler/com.sun.tools.javac.tree=ALL-UNNAMED
+--add-exports=jdk.compiler/com.sun.tools.javac.util=ALL-UNNAMED
+```
+
 The plugin adds a `google-java-format` formatter implementation that can be
 configured in `Window > Preferences > Java > Code Style > Formatter > Formatter
 Implementation`.