Linker argument order sometimes wrong.

[HildarTheDorf]

extern crates appear in the link arguments after #[link(name="foo")] attributes in the current crate. This can cause undefined symbol issues when an rlib contains an incomplete version of the static library foo (foo.a) because it is later in the linker command line. Forcing it to be last in the commandline with -C link-args="-lfoo" works as a workaround.
`
To be fair, I'm not sure if there is ever a "perfect" ordering for linker arguments that works in every single case (other than doing it manually), but making it extern crates, then #links in the current crate seems to make more sense. Something like #[link_first()] and/or #[link_last()] would work too (forcing it to link before or after external crates respectively).

This was all on Ubuntu 13.10 x86_64, and all the libs in question were static (.rlib or .a).

[alexcrichton]

Could you provide a small test case as an example? Last I tried I was unable to get a linker error when I tried things like this.

cc #11124

[HildarTheDorf]

Here's an attempt:
https://github.com/HildarTheDorf/RustLinkerBug

Type make to try and build. The list of #[link(name="")] might need amending (take a look at pkg-config --static --libs glfw3 for help, or read the rustc error message). Hopefully you eventually reach the point where glfw-rs functions can't find glfw symbols (and not other errors). You can comment out the #[link(name="glfw3")] to show how many symbols in glfw it IS finding.

Fails for me on ubuntu 13.10 x64 with 6532d2f, I'll update to master and check it still fails.

Note: I have glfw3.a in my linker search path, I can't see why dropping it in ./lib/ won't work, but I haven't tried it.

EDIT: Forgot to mention that adding -C link=args=-lglfw3 to RUSTFLAGS will successfully build, with the #[link(name="glfw3")] as well. You can also drop all the #[link()] stuff and just use -C link-args="'pkg-config --static --libs glfw3'" (backticks, not ', but markdown mangles it)