[build] Gradle 1.11 fails to build JFX

When you build with 1.11, you get this error:

…
:fxpackager:buildJavaFXPackager
:fxpackager:compileJava
Download http://jfx.us.oracle.com/imports/ant-1.8.2.jar
[ant:javac] Note: Some input files use unchecked or unsafe operations.
[ant:javac] Note: Recompile with -Xlint:unchecked for details.
:fxpackager:man
:fxpackager:processResources
:fxpackager:classes
:fxpackager:compileLauncher
:fxpackager:copyEmbeddedDT
:fxpackager:jar
:fxpackager:assemble
:graphics:compileDecoraJavaShaders
:graphics:generateDecoraNativeHeaders
:graphics:compileDecoraNativeShadersMac
:graphics:linkDecoraNativeShadersMac
:graphics:nativeDecora
:graphics:javahMacFont
:graphics:ccMacFont
/Users/steve/Documents/jfx-8u20/jfx/rt/modules/graphics/src/main/native-font/coretext.c:32:45: error: com_sun_javafx_font_coretext_OS.h: No such file or directory
:graphics:ccMacFont FAILED

FAILURE: Build failed with an exception.

* What went wrong:
Execution failed for task ':graphics:ccMacFont'.
> java.util.concurrent.ExecutionException: org.gradle.process.internal.ExecException: Process 'command 'gcc'' finished with non-zero exit value 1

* Try:
Run with --stacktrace option to get the stack trace. Run with --info or --debug option to get more log output.

BUILD FAILED

Total time: 1 mins 38.907 secs
Steve-Northovers-Oracle-MacBook-Pro:rt steve$