'assertion failed: !lib.is_empty()' on mingw-w64 (32bit)

[klutzy]

~/stone/rust-w32 $ rm build -rf && mkdir build && cd build
~/stone/rust-w32/build $ ../configure --build=i686-w64-mingw32
...
~/stone/rust-w32/build $ make
...
compile_and_link: i686-w64-mingw32/stage0/bin/rustc/i686-w64-mingw32/bin/rustc.dll
task 'rustc' failed at 'assertion failed: !lib.is_empty()', C:\bot\slave\snap3-win\build\src\librustc\metadata\cstore.rs:138
error: internal compiler error: unexpected failure

The failure doesn't happen on regular mingw.

[klutzy]

It's not mingw-w64 specific. librustc/lib/llvmdeps.rs contained #[link(name = "")] then rustc failed badly. I've opened #11073 for such glitches.