Fix build if oculusvr-sdk submodule is missing
Produce duplicate natives in the build, in preparation for removing
support for aliasing in native library loading.

Specifically, produce:

  jogl-all-noawt-natives-${os_and_arch}.jar
  jogl-all-mobile-natives-${os_and_arch}.jar
  jogl-all-android-natives-${os_and_arch}.jar