Currently, gcc doesn't support a multilib build for win64. I have been looking at how to do this, and have so far come up with a beginning to a solution. The work done thus far is part of this PR:
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=38294 The current blocker is in building libgcc. At some point in building libgcc, it gets down to the final compilation. In doing so, gcc is invoked with a -B option pointing to the 32-bit lib directory instead of the 64-bit lib directory. This works for building the 32-bit libgcc, but not the 64-bit default version. >From what I can tell, the -B option pointing to the 32-bit lib directory is in $(GCC_FOR_TARGET). Is that where it's supposed to be? Is there a way to make gcc search the right directory first (or at all)? What steps am I missing for enabling the multilib build? For reference, the system root and all of its libraries are installed into: $prefix/$target/lib and $prefix/$target/lib64, the latter of course being the 64-bit version of all the libs.
