very sketchy, how I (unknown who "I" is in this context; it is NOT sjburges@gimp.org) got it running:

- download tml's win32 builds of everything (gtk+2 etc.)
  http://www.gimp.org/win32
- download cygwin, including perl5.8

using Glib and Gtk2 from cvs (> 0.9)

tml's libs, pkg-config etc are all unpacked under /gnuwin32. if some dlls
are not in the bin dir, move them there:

   mv /gnuwin32/lib/*.dll /gnuwin32/bin

my /gnuwin32/bin looks like this:

   asprintf.dll        fttimer.exe                   intl.dll                 miniunz-static.exe  msgunfmt.exe            tiffdither.exe
   charset.dll         fttry.exe                     libatk-1.0-0.dll         miniunz.exe         msguniq.exe             tiffdump.exe
   example-static.exe  ftview.exe                    libfontconfig-1.dll      minizip-static.exe  ngettext.exe            tiffinfo.exe
   example.exe         gdk-pixbuf-csource.exe        libgdk-win32-2.0-0.dll   minizip.exe         pal2rgb.exe             tiffmedian.exe
   fax2ps.exe          gdk-pixbuf-query-loaders.exe  libgdk_pixbuf-2.0-0.dll  msgattrib.exe       pango-querymodules.exe  tiffset.exe
   fax2tiff.exe        gettext.exe                   libglib-2.0-0.dll        msgcat.exe          pkg-config.exe          tiffsplit.exe
   fc-cache.exe        gif2tiff.exe                  libgmodule-2.0-0.dll     msgcmp.exe          ppm2tiff.exe            untgz-static.exe
   fc-list.exe         glib-genmarshal.exe           libgobject-2.0-0.dll     msgcomm.exe         ras2tiff.exe            untgz.exe
   freetype-6.dll      glib-gettextize               libgthread-2.0-0.dll     msgconv.exe         rgb2ycbcr.exe           xgettext.exe
   freetype-config     glib-mkenums                  libgtk-win32-2.0-0.dll   msgen.exe           testnames.exe           xmlparse.dll
   ftbench.exe         gobject-query.exe             libpango-1.0-0.dll       msgexec.exe         thumbnail.exe           xmltok.dll
   ftdump.exe          gspawn-win32-helper.exe       libpangoft2-1.0-0.dll    msgfilter.exe       tiff2bw.exe             xmlwf.exe
   ftlint.exe          gtk-demo.exe                  libpangowin32-1.0-0.dll  msgfmt.exe          tiff2ps.exe             zlib-1.dll
   ftmemchk.exe        gtk-query-immodules-2.0.exe   libtiff.dll              msggrep.exe         tiff2rgba.exe
   ftmulti.exe         iconv.dll                     minigzip-static.exe      msginit.exe         tiffcmp.exe
   ftstring.exe        iconv.exe                     minigzip.exe             msgmerge.exe        tiffcp.exe

(note pkg-config!)

WARNING, THIS IS A BIG UNSUPPORTED HACK (just as windows itself)

    PATH=/gnuwin32/bin:$PATH

    cd Glib
    perl Makefile.PL
    make CC="gcc -mms-bitfields" LDLOADLIBS="$(pkg-config gthread-2.0 gmodule-2.0 gobject-2.0 --libs) -lintl"
    make test
    make install

    cd Gtk2
    perl Makefile.PL
    make CC="gcc -mms-bitfields" LDLOADLIBS="$(pkg-config gthread-2.0 gtk+-2.0 --libs) -lintl -L/usr/lib/perl5/site_perl/5.8.0/cygwin-multi-64int/auto/Glib/ -lGlib"
    make install

    cd gimp-1.3
    CC="gcc -mms-bitfields" ./configure --prefix=/gimp
    make
    make install