Linking fails when using a crate name alias

[brson]

use stdlib(name = "std");                                                                                                                                                     

fn main() {                                                                                                                                                                   
}                                                                                                                                                                             

error: linking with gcc failed with code 1
note: gcc arguments: -L/home/brian/dev/rust/build/x86_64-unknown-linux-gnu/stage1/lib/rustc/x86_64-unknown-linux-gnu/lib -m64 -o x86_64-unknown-linux-gnu/test/run-pass/corelib.stage1-x86_64-unknown-linux-gnu x86_64-unknown-linux-gnu/test/run-pass/corelib.o -L/home/brian/dev/rust/build/x86_64-unknown-linux-gnu/stage1/lib/rustc/x86_64-unknown-linux-gnu/lib -lcore-14bd852465126fe7-0.1 -L/home/brian/dev/rust/build/x86_64-unknown-linux-gnu/stage1/lib/rustc/x86_64-unknown-linux-gnu/lib -lstd-79ca5fac56b63fde-0.1 -lm -lrustrt -lrt -ldl -lmorestack -Wl,-rpath,$ORIGIN/../../stage1/lib/rustc/x86_64-unknown-linux-gnu/lib -Wl,-rpath,/home/brian/dev/rust/build/x86_64-unknown-linux-gnu/stage1/lib/rustc/x86_64-unknown-linux-gnu/lib -Wl,-rpath,/home/brian/dev/rust-install/lib/rustc/x86_64-unknown-linux-gnu/lib
note: x86_64-unknown-linux-gnu/test/run-pass/corelib.o:(.data.rel+0x10): undefined reference to `_rust_crate_map_stdlib'
collect2: ld returned 1 exit status

error: aborting due to previous errors

[lht]

Progress update: Patch 6632f145b3d03054d6c89d867b4d3495c326c906 works on Mac&Linux, but failed on Windows. Error like:

error: linking with gcc failed with code 1 note: gcc arguments: 
......
note: i686-pc-mingw32/stage2/bin/rustc/i686-pc-mingw32/bin/run_pass_stage2.o:(.data+0xc): 
undefined reference to `_rust_crate_map_std9' collect2: ld returned 1 exit status 

[lht]

Just noticed a FIXME at https://github.com/mozilla/rust/blob/master/src/comp/middle/trans/base.rs#L5415

The crate_hash is available now by metadata::decoder::get_crate_hash, so I guess we should switch to hashes. Hopefully this could workaround the mysterious fault on Windows.