Do not follow symlinks when looking for the stdlib files.

[vitor1001]

This aligns MiniZinc with the standard behavior of *nix binaries that when a tool expects some directory hierarchy, that must match the reality before following any eventual symlinks, not after.

In particular, the Bazel build system uses a lot of symlinks, making the behavior before this CL particularly confusing.

[guidotack]

We're considering the switch to C++17, which would enable the use of std::filesystem::path::lexically_normal (among other filesystem functions). As far as I can see, that would also fix this issue, and it would have the added bonus of being platform independent (we currently need Windows-specific code here).
It would be great to hear if that would solve the issue for you, and whether you can you see any other downsides of this approach.

[vitor1001]

Hi Guido!

Yes, a much simpler implementation using std::filesystem works for us. Here is what I tested:

std::string file_path(const std::string& filename, const std::string& basePath) {
  std::filesystem::path path(filename);
  if (!basePath.empty() && !path.is_absolute()) {
    path = std::filesystem::path(basePath) / path;
  }

  if (!path.is_absolute()) {
    path = std::filesystem::current_path() / path;
  }

  return path.lexically_normal();
}