I have the same problem with the new tools that was discussed above and never resolved as far as I can tell. My WinXP SP3 system just does not like gcc 4.6.3. Immediately after creating the obj directories, I get errors with either cc1.exe or cc1plus.exe.

make TARGET=mess
Compiling src/osd/windows/vconv.c...
cc1.exe: internal compiler error: Illegal instruction
Please submit a full bug report,
with preprocessed source if appropriate.
See <http://gcc.gnu.org/bugs.html> for instructions.
make: *** [obj/windows/osd/windows/vconv.o] Error 1

OR

make TARGET=mess OSD=winui
Compiling src/build/file2str.c...
cc1plus.exe: internal compiler error: Illegal instruction
Please submit a full bug report,
with preprocessed source if appropriate.
See <http://gcc.gnu.org/bugs.html> for instructions.
make: *** [obj/winui/build/file2str.o] Error 1

So now I'm blocked by either Python or gcc 4.6.3 from compiling MESS.