Hi all,
In fact the file needing a patch to #include <cstddef> to compile with
gcc-4.6 are not difficult to find, a little grep suffices ;)
===========
dd@darkstar:/tmp/qt-x11-free-3.3.8b$ find . -iname \*.h -exec grep -L "#include <cstddef>" {} \; | xargs grep -l ptrdiff_t
./src/tools/qvaluelist.h
./src/tools/qvaluevector.h
./src/tools/qmap.h
./src/3rdparty/zlib/zutil.h
./include/qmap.h
./include/qvaluevector.h
./include/qvaluelist.h
dd@darkstar:/tmp/qt-x11-free-3.3.8b$ find . -iname \*.h -exec grep -L "#include <cstddef>" {} \; | xargs grep -l size_t
./src/sql/qsqlrecord.h
./src/tools/qvaluelist.h
./src/tools/qvaluevector.h
./src/tools/qmap.h
./src/kernel/qrichtext_p.h
./src/3rdparty/libjpeg/jinclude.h
./src/3rdparty/libjpeg/jpegint.h
./src/3rdparty/libjpeg/jpeglib.h
./src/3rdparty/libjpeg/jmemsys.h
./src/3rdparty/libjpeg/jdhuff.h
./src/3rdparty/libmng/libmng_memory.h
./src/3rdparty/libmng/libmng_types.h
./src/3rdparty/libpng/pngconf.h
./src/3rdparty/libpng/png.h
./src/3rdparty/opentype/ftglue.h
./tools/designer/designer/defs.h
./mkspecs/qnx-g++/qplatformdefs.h
./mkspecs/aix-g++-64/qplatformdefs.h
./mkspecs/tru64-g++/qplatformdefs.h
./mkspecs/tru64-cxx/qplatformdefs.h
./mkspecs/bsdi-g++/qplatformdefs.h
./mkspecs/irix-g++/qplatformdefs.h
./mkspecs/aix-xlc-64/qplatformdefs.h
./mkspecs/unixware-cc/qplatformdefs.h
./mkspecs/solaris-g++/qplatformdefs.h
./mkspecs/irix-cc-64/qplatformdefs.h
./mkspecs/sco-cc/qplatformdefs.h
./mkspecs/unixware-g++/qplatformdefs.h
./mkspecs/reliant-cds/qplatformdefs.h
./mkspecs/aix-g++/qplatformdefs.h
./mkspecs/aix-xlc/qplatformdefs.h
./mkspecs/solaris-cc/qplatformdefs.h
./mkspecs/irix-cc/qplatformdefs.h
./examples/distributor/distributor.ui.h
./include/qmap.h
./include/qvaluevector.h
./include/qvaluelist.h
./include/qsqlrecord.h
./include/private/qrichtext_p.h
===========
(this is a result from doing the grep commands into unpatched qt-3.3.8b).
This method should also work with the Trinity sources.