JDK build fails on missing javah

[Nir Lisker]

After successfully building OpenJFX (11) Iv'e went on to build OpenJDK (11)
as instructed under "Integration with OpenJDK" (
http://hg.openjdk.java.net/jdk/jdk/raw-file/tip/doc/building.html).

When executing `bash configure
--with-import-modules=jfx_path\rt\build\modular-sdk` the build fails:

checking for java in Boot JDK... ok
checking for javac in Boot JDK... ok
checking for javah in Boot JDK... not found
configure: Your Boot JDK seems broken. This might be fixed by explicitly
setting --with-boot-jdk
configure: error: Could not find javah in the Boot JDK
configure exiting with result code 1

The boot JDK is 10, which does not have javah anymore, so it is no
surprise. I could point boot JDK to a previous version, but I don't think I
should. Does anyone know what I should do?

Nir