OpenJDK 6 fails to build without pre-compiled headers

In file included from /home/tdaitx/openjdk-6-6b40-1.13.12/build/openjdk-ecj/hotspot/src/share/vm/oops/arrayKlassKlass.cpp:33:0:
/home/tdaitx/openjdk-6-6b40-1.13.12/build/openjdk-ecj/hotspot/src/share/vm/gc_implementation/parallelScavenge/psPromotionManager.inline.hpp: In member function 'oopDesc* PSPromotionManager::copy_to_survivor_space(oop)':
/home/tdaitx/openjdk-6-6b40-1.13.12/build/openjdk-ecj/hotspot/src/share/vm/gc_implementation/parallelScavenge/psPromotionManager.inline.hpp:131:37: error: invalid use of incomplete type 'class PSOldGen'

            new_obj = (oop)old_gen()->cas_allocate(new_obj_size);
                                     ^
In file included from /home/tdaitx/openjdk-6-6b40-1.13.12/build/openjdk-ecj/hotspot/src/share/vm/gc_implementation/parallelScavenge/psParallelCompact.hpp:30:0,
                 from /home/tdaitx/openjdk-6-6b40-1.13.12/build/openjdk-ecj/hotspot/src/share/vm/gc_implementation/shared/markSweep.inline.hpp:32,
                 from /home/tdaitx/openjdk-6-6b40-1.13.12/build/openjdk-ecj/hotspot/src/share/vm/oops/oop.inline.hpp:29,
                 from /home/tdaitx/openjdk-6-6b40-1.13.12/build/openjdk-ecj/hotspot/src/share/vm/classfile/classFileParser.hpp:30,
                 from /home/tdaitx/openjdk-6-6b40-1.13.12/build/openjdk-ecj/hotspot/src/share/vm/classfile/classLoader.hpp:28,
                 from /home/tdaitx/openjdk-6-6b40-1.13.12/build/openjdk-ecj/hotspot/src/share/vm/classfile/systemDictionary.hpp:29,
                 from /home/tdaitx/openjdk-6-6b40-1.13.12/build/openjdk-ecj/hotspot/src/share/vm/classfile/javaClasses.hpp:28,
                 from /home/tdaitx/openjdk-6-6b40-1.13.12/build/openjdk-ecj/hotspot/src/share/vm/oops/arrayKlassKlass.cpp:26:
/home/tdaitx/openjdk-6-6b40-1.13.12/build/openjdk-ecj/hotspot/src/share/vm/gc_implementation/parallelScavenge/psCompactionManager.hpp:38:7: error: forward declaration of 'class PSOldGen'
 class PSOldGen;
       ^
In file included from /home/tdaitx/openjdk-6-6b40-1.13.12/build/openjdk-ecj/hotspot/src/share/vm/oops/arrayKlassKlass.cpp:33:0:
/home/tdaitx/openjdk-6-6b40-1.13.12/build/openjdk-ecj/hotspot/src/share/vm/gc_implementation/parallelScavenge/psPromotionManager.inline.hpp:136:43: error: invalid use of incomplete type 'class PSOldGen'
             HeapWord* lab_base = old_gen()->cas_allocate(OldPLABSize);
                                           ^
In file included from /home/tdaitx/openjdk-6-6b40-1.13.12/build/openjdk-ecj/hotspot/src/share/vm/gc_implementation/parallelScavenge/psParallelCompact.hpp:30:0,
                 from /home/tdaitx/openjdk-6-6b40-1.13.12/build/openjdk-ecj/hotspot/src/share/vm/gc_implementation/shared/markSweep.inline.hpp:32,
                 from /home/tdaitx/openjdk-6-6b40-1.13.12/build/openjdk-ecj/hotspot/src/share/vm/oops/oop.inline.hpp:29,
                 from /home/tdaitx/openjdk-6-6b40-1.13.12/build/openjdk-ecj/hotspot/src/share/vm/classfile/classFileParser.hpp:30,
                 from /home/tdaitx/openjdk-6-6b40-1.13.12/build/openjdk-ecj/hotspot/src/share/vm/classfile/classLoader.hpp:28,
                 from /home/tdaitx/openjdk-6-6b40-1.13.12/build/openjdk-ecj/hotspot/src/share/vm/classfile/systemDictionary.hpp:29,
                 from /home/tdaitx/openjdk-6-6b40-1.13.12/build/openjdk-ecj/hotspot/src/share/vm/classfile/javaClasses.hpp:28,
                 from /home/tdaitx/openjdk-6-6b40-1.13.12/build/openjdk-ecj/hotspot/src/share/vm/oops/arrayKlassKlass.cpp:26:
/home/tdaitx/openjdk-6-6b40-1.13.12/build/openjdk-ecj/hotspot/src/share/vm/gc_implementation/parallelScavenge/psCompactionManager.hpp:38:7: error: forward declaration of 'class PSOldGen'
 class PSOldGen;
       ^
make[8]: *** [arrayKlassKlass.o] Error 1