Philipp Stephani wrote:
> All of the current directory functions exhibit this behavior, including
> getwd and getcwd, so you need to make sure they are also covered.

Thanks for letting us know. I installed the 2nd attached patch, which addresses 
this by making the patch behave more like what you originally proposed, while 
still avoiding the need to use file_name_absolute_p (which is about Emacs file 
names, not OS names). Also, I noticed a related memory leak and fixed that by 
installing the 1st attached patch.