JDK-8044773 introduced:
http://hg.openjdk.java.net/jdk9/dev/jdk/file/46dfc09b2c76/src/jdk.net/share/classes/jdk/net/ExtendedSocketOptions.java

Which is using:
import jdk.internal.misc.JavaIOFileDescriptorAccess;
import jdk.internal.misc.SharedSecrets;

But the module-info.java for java.base does not export jdk.internal.misc to jdk.net:
http://hg.openjdk.java.net/jdk9/dev/jdk/file/46dfc09b2c76/src/java.base/share/classes/module-info.java#l158

So the OpenJDK build fails with:
/localhome/langtools/.jenkins/jobs/build-jdk9-with-patch/workspace/dev/jdk/src/jdk.net/share/classes/jdk/net/ExtendedSocketOptions.java:35: error: package jdk.internal.misc does not exist
import jdk.internal.misc.JavaIOFileDescriptorAccess;
                        ^
/localhome/langtools/.jenkins/jobs/build-jdk9-with-patch/workspace/dev/jdk/src/jdk.net/share/classes/jdk/net/ExtendedSocketOptions.java:36: error: package jdk.internal.misc does not exist
import jdk.internal.misc.SharedSecrets;
                        ^
/localhome/langtools/.jenkins/jobs/build-jdk9-with-patch/workspace/dev/jdk/src/jdk.net/share/classes/jdk/net/ExtendedSocketOptions.java:146: error: cannot find symbol
    private static final JavaIOFileDescriptorAccess fdAccess =
                         ^
  symbol: class JavaIOFileDescriptorAccess
  location: class ExtendedSocketOptions
/localhome/langtools/.jenkins/jobs/build-jdk9-with-patch/workspace/dev/jdk/src/jdk.net/share/classes/jdk/net/ExtendedSocketOptions.java:147: error: cannot find symbol
            SharedSecrets.getJavaIOFileDescriptorAccess();
            ^
  symbol: variable SharedSecrets
  location: class ExtendedSocketOptions
4 errors