include doesn't support UNC paths on Windows

[kornelski]

let cc = gcc::Config::new();
cc.include(std::fs::canonicalize("."));

Doesn't add absolute path of "." as the include dir (tested on Win10, MSVC). This is because Rust's canonicalize() makes a UNC path such as \\?\C:\Foo.

Stripping the \\?\ prefix seems to solve the problem, but I don't know enough about UNC paths to know whether that's a good solution.

I use fs::canonicalize() as the easiest way to get absolute paths in build scripts of link/-sys dependencies to reliably pass the paths in env vars for other packages to consume, and it works well on Unix.

[alexcrichton]

Is this a bug with gcc-rs? Or is this a bug with cl.exe not accepting these paths? Do you have an error message?

[kornelski]

cl.exe doesn't support UNC paths (-IC:\foo works as expected, -I\\?\C:\foo doesn't find includes)

So strictly speaking that's a bug in cl.exe, but I'm betting on gcc-rs to hide deficiencies of MSVC for me :)

[kornelski]

I've released a crate that normalizes paths in a compatible way: https://gitlab.com/kornelski/dunce

It would be nice if that was built into the include() function here.

[alexcrichton]

I'm going to close this since it sounds like it was a bug in cl.exe, and I'd prefer to not add too much normalization to this crate.