how to build without precompiled headers?

[Matthias Klose]

Trying to track down an ICE (internal compiler error), I need to build hotspot
without precompiled header files.  There is a macro USE_PRECOMPILED_HEADER
defined in openjdk/hotspot/make/*/makefiles/gcc.make, but just removing the
conditional around this definition still builds using precompiled header files.
How can you build without precompiled header files (even if it's a hack)?

  Matthias