Tools are compiled with cross-compiler

Please see here for some discussion on this issue:
http://qt-project.org/forums/viewthread/24090/

I have built a cross toolchain for an x86_64 target. The linker doesn't support the -m64 option.

After I run configure, then run make, it starts building the tools, and fails with ld: unrecognised emulation mode: 64.

While it's building the tools, I noticed it's using my cross-compiler, not the host compiler. And I've removed the -m64 from CFLAGS and LFLAGS in my custom mkspec, but it's still using -m64 on both the compiler and the linker (it appears to be picking them up from linux-g++-64).

I configured Qt with:
-platform=linux-g++-64
-xplatform=<my mkspec>

I also tried using -device instead of/in addition to -xplatform, but it's still using the cross-compiler (and mixing in the linux-g++-64 CFLAGS) when building the tools.