Fix compiling on Windows

src/zig.rs

@@ -565,7 +565,7 @@ fn write_linker_wrapper(path: &Path, command: &str, args: &str) -> Result<()> {
  env::current_exe()?
  };
  let current_exe = if is_mingw_shell() {
- current_exe.to_slash_lossy()
+ current_exe.to_slash_lossy().to_string()
  } else {
  current_exe.display().to_string()
  };