FTBFS on RHEL-7 with rustc 1.24.0

[mcepl]

If you are reporting a bug, please read following FAQ first. If you are
requesting new features or other types of questions, you can ignore it.

If you are still seeing an error or other types of issue, please create ticket with

• neovim/vim version vim8 8.0.1520 (but we haven't even got to the state where this would be relevant)
• Plugin version (git SHA) 6f46c92
• Minimal vimrc (e.g. https://github.com/autozimu/LanguageClient-neovim/blob/next/min-init.vim)
• Language server name/link and version python-language-server 0.14.0
• Reproduction steps (from clean state)
  1. git checkout next
  2. make release

[A lot of other non-problematic lines removed]

Compiling structopt-derive v0.1.6
error[E0523]: found two different crates with name `std` that are not distinguished by differing `-C metadata`. This will result in symbol conflicts between the two.
   --> /home/matej/.cargo/registry/src/github.com-1ecc6299db9ec823/synstructure-0.6.1/src/lib.rs:137:1
    |
137 | extern crate proc_macro;
    | ^^^^^^^^^^^^^^^^^^^^^^^^

error: Could not compile `synstructure`.
warning: build failed, waiting for other jobs to finish...
error[E0523]: found two different crates with name `std` that are not distinguished by differing `-C metadata`. This will result in symbol conflicts between the two.
   --> /home/matej/.cargo/registry/src/github.com-1ecc6299db9ec823/structopt-derive-0.1.6/src/lib.rs:278:1
    |
278 | extern crate proc_macro;
    | ^^^^^^^^^^^^^^^^^^^^^^^^

error: Could not compile `structopt-derive`.
warning: build failed, waiting for other jobs to finish...
error: build failed
make: *** [release] Error 101

[mcepl]

Ah, got it, https://bugzilla.redhat.com/show_bug.cgi?id=1546541 (or rust-lang/rust#48319)