after 2016-02-24, rust-std-nightly-arm* tarballs ship with less `.rlib`s and almost no `.so`s

[japaric]

STR

$ curl -sL 'https://static.rust-lang.org/dist/2016-03-23/rust-std-nightly-armv7-unknown-linux-gnueabihf.tar.gz' | tar --strip-components 1 -xz
$ tree rust-std-armv7-unknown-linux-gnueabihf/lib/rustlib/armv7-unknown-linux-gnueabihf/lib
├── liballoc-10e97cc6.rlib
├── liballoc_jemalloc-10e97cc6.rlib
├── liballoc_system-10e97cc6.rlib
├── libarena-10e97cc6.rlib
├── libarena-10e97cc6.so
├── libcollections-10e97cc6.rlib
├── libcompiler-rt.a
├── libcore-10e97cc6.rlib
├── libflate-10e97cc6.rlib
├── libflate-10e97cc6.so
├── libgetopts-10e97cc6.rlib
├── libgetopts-10e97cc6.so
├── libgraphviz-10e97cc6.rlib
├── libgraphviz-10e97cc6.so
├── liblibc-10e97cc6.rlib
├── liblog-10e97cc6.rlib
├── liblog-10e97cc6.so
├── librand-10e97cc6.rlib
├── librbml-10e97cc6.rlib
├── librbml-10e97cc6.so
├── librustc_bitflags-10e97cc6.rlib
├── librustc_unicode-10e97cc6.rlib
├── libserialize-10e97cc6.rlib
├── libserialize-10e97cc6.so
├── libstd-10e97cc6.rlib
├── libstd-10e97cc6.so
├── libterm-10e97cc6.rlib
├── libterm-10e97cc6.so
├── libtest-10e97cc6.rlib
└── libtest-10e97cc6.so

$ curl -sL 'https://static.rust-lang.org/dist/2016-03-24/rust-std-nightly-armv7-unknown-linux-gnueabihf.tar.gz' | tar --strip-components 1 -xz
$ tree rust-std-armv7-unknown-linux-gnueabihf/lib/rustlib/armv7-unknown-linux-gnueabihf/lib
├── liballoc-8250b9d58dbcb765.rlib
├── liballoc_jemalloc-09807bb22a185088.rlib
├── liballoc_system-4bf32b7cb9861654.rlib
├── libcollections-03ff6b8167d2df61.rlib
├── libcompiler-rt.a
├── libcore-28829d33c69225e4.rlib
├── liblibc-9de2ff21354cb608.rlib
├── librand-ff6d915f814fe089.rlib
├── librustc_unicode-b372888cd484ca87.rlib
├── libstd-1d20f6bd73ff8b5a.rlib
└── libstd-1d20f6bd73ff8b5a.so

Most likely the cause is that this std component is now being produced using rustbuild.

I don't particularly mind the lack of .sos but the libtest.rlib is important to me because I use it to cross compile unit tests to ARM which then I run under QEMU. But now I'm getting can't find the crate for test errors.

cc @alexcrichton

[alexcrichton]

Bah right, this is actually a problem I forgot to address with rustbuild in general. Right now it has two main phases of compilation, the standard library and the compiler. It assumes that the compiler is for hosts and the standard library is only for targets, but this isn't true as libtest is part of the target suite we distribute.

This seems like it's straight up just a rustbuild bug.