pypa/virtualenv — pull request #663 by techtonik (2014-10-29 20:04:12+00:00)
Title: Autodetect if symlinks are supported on target file system

This detects symlink suppot on destination filesystem and not only in Python interpreter or OS. If symlinks are not supported, falls back to copy behavior.

This fixes some case reported in #92 and #409, without specifying `--always-copy` explicitly.

Ideal case would be to invert `virtualenv` symlinking behavior - symlink only when explicitly requested.