$ cd ~/tmp
$ export PATH=$PATH:/home/it/usr/rust-61443dc/bin
$ cat o_o.rs
extern mod extra;
fn main() {}

$ rustc.exe o_o.rs
error: linking with `g++` failed: exit code: 1
note: g++ arguments: '-m32' '-LC:\home\usr\rust-61443dc\bin\rustc\i686-pc-mingw32\bin' '-o' 'o_o' 'o_o.o' 'C:\home\usr\rust-61443dc\bin\rustc\i686-pc-mingw32\bin\libstd-6425b930ca146ae9-0.9-pre.rlib' 'C:\home\usr\rust-61443dc\bin\rustc\i686-pc-mingw32\bin\librustuv-a13edc95d75df17-0.9-pre.rlib' '-lpthread' '-lws2_32' '-lpsapi' '-liphlpapi'
'C:\home\usr\rust-61443dc\bin\rustc\i686-pc-mingw32\bin\libextra-aaa96aab146eb38e-0.9-pre.rlib' '-lrustrt' '-LC:\home\tmp\.rust' '-LC:\home\tmp' '-lmorestack'
note: c:/home/usr/mingw-20120426/bin/../lib/gcc/mingw32/4.6.2/../../../../mingw32/bin/ld.exe: cannot find -lrustrt