The MacOS file system is not case sensitive.
Thus, the Lean path normalization function converts all characters in the pathname to lowercase.
We use the auxiliary Python script relative.py in our makefile.
The Python function `os.path.relpath` normalizes pathnames, but it only converts all characters to lowercase on Windows :(
Thus, Lean outputs the dependency files such as
```
/users/leonardodemoura/projects/lean4/library/init/lean/smap.olean
```
In Python, the current directory is
```
/Users/leonardodemoura/projects/lean4/library
```
Thus, `os.path.relpath` produces
```
../../../../../users/leonardodemoura/projects/lean4/library/init/lean/smap.olean
```
instead of
```
init/lean/smap.olean
```
