`make check-stage1-std` is broken

[catamorphism]

Even after wiping away what I thought was enough of the build directory, and reconfiguring, make check-stage1-std failed with:

compile_and_link: x86_64-apple-darwin/stage1/test/stdtest-x86_64-apple-darwin
/Users/tjc/rust3/src/libstd/core.rc:1:0: 1:0 error: can't find crate for `extra`
/Users/tjc/rust3/src/libstd/core.rc:1 // Copyright 2012-2013 The Rust Project Developers. See the COPYRIGHT

Something's strange here. I assume it's to do with the renaming. make check-stage1-extra does work.

[alexcrichton]

This was fixed by d7e1f08