To reproduce:

1. Set JAVA_HOME to an OpenJDK build (i.e., a JDK that does not have javafx.* modules)

2. Run the following build command:

$ gradle -PCOMPILE_MEDIA=true

3. BUG: This will fail with the following error:

:media:compileToolsJava
.../jfx-dev/rt/modules/javafx.media/src/tools/java/headergen/HeaderGen.java:28: error: package com.sun.media.jfxmedia does not exist
import com.sun.media.jfxmedia.MediaError;
                             ^
.../jfx-dev/rt/modules/javafx.media/src/tools/java/headergen/HeaderGen.java:43: error: cannot find symbol
        for (MediaError error : MediaError.values()) {
                                ^
  symbol: variable MediaError
  location: class HeaderGen
.../jfx-dev/rt/modules/javafx.media/src/tools/java/headergen/HeaderGen.java:43: error: cannot find symbol
        for (MediaError error : MediaError.values()) {
             ^
  symbol: class MediaError
  location: class HeaderGen
.../jfx-dev/rt/modules/javafx.media/src/tools/java/headergen/HeaderGen.java:64: error: cannot find symbol
                    String errorFilePath = arg[1] + "/" + MediaError.class.getCanonicalName().replace(".", "/") + ".java";
                                                          ^
  symbol: class MediaError
  location: class HeaderGen
4 errors

BUILD FAILED in 4m 37s