make buildworld failing

[kyuupichan]

make buildworld is failing with a clean obj directory and latest sources for me during the mkdep stage early on:

$ uname -a
DragonFly athlon2.akihabara.co.uk 3.3-DEVELOPMENT DragonFly v3.3.0.944.g5ef30-DEVELOPMENT #2: Mon Jan 14 15:53:11 JST 2013     root at athlon2.akihabara.co.uk:/usr/obj/usr/src/sys/X86_64_GENERIC  x86_64

This appears to be where it starts to go wrong, with an "ignoring stale .depend":

===> gnu/lib/gcc44/libstdc++
building static stdc++ library
rm -f libstdc++.a
ar cq libstdc++.a `lorder array_type_info.o atexit_arm.o bad_cast.o bad_typeid.o class_type_info.o del_op.o del_opnt.o del_opv.o del_opvnt.o dyncast.o eh_alloc.o eh_arm.o eh_aux_runtime.o eh_call.o eh_catch.oThis appears to be where it starts to go wrong: eh_exception.o eh_globals.o eh_personality.o eh_ptr.o eh_term_handler.o eh_terminate.o eh_throw.o eh_type.o eh_unex_handler.o enum_type_info.o function_type_info.o fundamental_type_info.o guard.o new_handler.o new_op.o new_opnt.o new_opv.o new_opvnt.o pbase_type_info.o pmem_type_info.o pointer_type_info.o pure.o si_class_type_info.o tinfo.o tinfo2.o vec.o vmi_class_type_info.o vterminate.o cp-demangle.o atomic.o bitmap_allocator.o pool_allocator.o mt_allocator.o codecvt.o compatibility.o complex_io.o ctype.o debug.o functexcept.o hash.o hash_c++0x.o globals_io.o hashtable.o hashtable_c++0x.o ios.o ios_failure.o ios_init.o ios_locale.o limits.o limits_c++0x.o list.o debug_list.o locale.o locale_init.o locale_facets.o localename.o math_stubs_float.o math_stubs_long_double.o stdexcept.o strstream.o system_error.o tree.o allocator-inst.o concept-inst.o fstream-inst.o ext-inst.o ios-inst.o iostream-inst.o istream-inst.o istream.o locale-inst.o misc-inst.o ostream-inst.o sstream-inst.o streambuf-inst.o streambuf.o string-inst.o valarray-inst.o wlocale-inst.o wstring-inst.o mutex.o condition_variable.o chrono.o thread.o atomicity.o codecvt_members.o collate_members.o ctype_members.o messages_members.o monetary_members.o numeric_members.o time_members.o basic_file_stdio.o c_locale.o  | tsort -q` 
ranlib libstdc++.a
make: ignoring stale .depend for /usr/obj/usr/src/world_x86_64/usr/lib/libm.a
building shared library libstdc++.so.9
rm -f libstdc++.so.9 libstdc++.so
ln -fs libstdc++.so.9 libstdc++.so
cc  -shared -Wl,-x  -o libstdc++.so.9 -Wl,-soname,libstdc++.so.9  `lorder array_type_info.So atexit_arm.So bad_cast.So bad_typeid.So class_type_info.So del_op.So del_opnt.So del_opv.So del_opvnt.So dyncast.So eh_alloc.So eh_arm.So eh_aux_runtime.So eh_call.So eh_catch.So eh_exception.So eh_globals.So eh_personality.So eh_ptr.So eh_term_handler.So eh_terminate.So eh_throw.So eh_type.So eh_unex_handler.So enum_type_info.So function_type_info.So fundamental_type_info.So guard.So new_handler.So new_op.So new_opnt.So new_opv.So new_opvnt.So pbase_type_info.So pmem_type_info.So pointer_type_info.So pure.So si_class_type_info.So tinfo.So tinfo2.So vec.So vmi_class_type_info.So vterminate.So cp-demangle.So atomic.So bitmap_allocator.So pool_allocator.So mt_allocator.So codecvt.So compatibility.So complex_io.So ctype.So debug.So functexcept.So hash.So hash_c++0x.So globals_io.So hashtable.So hashtable_c++0x.So ios.So ios_failure.So ios_init.So ios_locale.So limits.So limits_c++0x.So list.So debug_list.So locale.So locale_init.So locale_facets.So localename.So math_stubs_float.So math_stubs_long_double.So stdexcept.So strstream.So system_error.So tree.So allocator-inst.So concept-inst.So fstream-inst.So ext-inst.So ios-inst.So iostream-inst.So istream-inst.So istream.So locale-inst.So misc-inst.So ostream-inst.So sstream-inst.So streambuf-inst.So streambuf.So string-inst.So valarray-inst.So wlocale-inst.So wstring-inst.So mutex.So condition_variable.So chrono.So thread.So atomicity.So codecvt_members.So collate_members.So ctype_members.So messages_members.So monetary_members.So numeric_members.So time_members.So basic_file_stdio.So c_locale.So | tsort -q` -lm
/usr/obj/usr/src/ctools_x86_64_x86_64/usr/libexec/binutils222/elf/ld.bfd: cannot find -lm
*** Error code 1

Stop.

Any ideas?  I'm stumped.

Neil.