To reproduce:

1. Clone the jdk/jdk10 repo (or jdk/jdk repo and update to the jdk-10+36 tag)

2. Build the JDK (make images)

3. Note that the javah launcher is missing, which is intentional (see JDK-8193503 and JDK-8191054)

* Alternative to steps 1-3: take the latest build of JDK 10 (or even JDK 9) and remove $JAVA_HOME/bin/javah

4. Try to build JavaFX using this JDK:

$ gradle
...
FAILURE: Build failed with an exception.

* Where:
Build file '/localhome/kcr/javafx/openjfx/jfx-kcr/rt/build.gradle' line: 1034

* What went wrong:
A problem occurred evaluating root project 'rt'.
> Missing or incorrect path to 'javah': '/localhome/kcr/jdks/jdk-10/bin/javah'. Perhaps bad JDK_HOME? /localhome/kcr/jdks/jdk-10