Add work around for bug in cross compilation

[rylev]

This should fix #614. I can now successfully document windows-rs on Linux against the x86_64-pc-windows-msvc target.

[jyn514]

So, I looked at this some more this morning, and something very strange is going on:

• On NixOS, with rustc 1.52.0-nightly (1705a7d64 2021-03-18), cargo doc --no-deps panics while compiling windows_gen
• On Debian 10, with the same version of nightly, cargo doc --no-deps works fine.
• On NixOS, with rustc 1.51.0-beta.8 (73f48e5f6 2021-03-18), cargo doc --no-deps works fine.
• On NixOS with this change and nightly, I get an error:

error: /nix/store/9rabxvqbv0vgjmydiv59wkz768b5fmbc-glibc-2.30/lib/libc.so.6: version `GLIBC_2.32' not found (required by /home/joshua/windows-rs/target/debug/deps/libwindows_gen_macros-c30ffbab983c7445.so)
 --> crates/gen/src/lib.rs:2:1
  |
2 | extern crate windows_gen_macros as macros;
  | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

[rylev]

@jyn514 The libc error is strange. Does a "hello, world" app compile file?

[jyn514]

@jyn514 The libc error is strange. Does a "hello, world" app compile file?

Hello world works but installing cargo bisect-rustc does not, so this is probably an environment problem. Weird that it only shows up on nightly.

What OS are you using to compile? It seems weird that this works on Debian 10 but ICEs on NixOS.

[rylev]

I'm compiling on Windows 10 and WSL with an Ubuntu environment. I'm assuming you get this when you cargodoc is running and not while building. Can you try breaking up the build and run step into two?

[jyn514]

No, I get this error while building, not documenting.

[joshua@uhura:~/windows-rs]$ git checkout FETCH_HEAD
HEAD is now at 59557f0 Merge branch 'master' into fix-cross-compilation

[joshua@uhura:~/windows-rs]$ cargo check
   Compiling windows_gen v0.5.0 (/home/joshua/windows-rs/crates/gen)
error: /nix/store/9rabxvqbv0vgjmydiv59wkz768b5fmbc-glibc-2.30/lib/libc.so.6: version `GLIBC_2.32' not found (required by /home/joshua/windows-rs/target/debug/deps/libwindows_gen_macros-c30ffbab983c7445.so)
 --> crates/gen/src/lib.rs:2:1
  |
2 | extern crate windows_gen_macros as macros;
  | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[joshua@uhura:~/windows-rs]$ git checkout master
Switched to branch 'master'
Your branch is up to date with 'origin/master'.
[joshua@uhura:~/windows-rs]$ cargo check
   Compiling windows_gen v0.5.0 (/home/joshua/windows-rs/crates/gen)
thread 'rustc' panicked at 'Failed to get crate data for crate19', compiler/rustc_metadata/src/creader.rs:136:32

[kennykerr]

Hopefully the actual bug will get fixed but this does unblock x86 builds in my experience as well.

[kennykerr]

And just to be clear, this workaround is for the rustc cross compilation bug but does not address the cargo hang bug mentioned in #614.