osutil: export a "getfstype" method This patch exports the "getfstype" method. So we can use it to enable hardlinks for known safe filesystems. The patch was tested manually via debugshell on a Linux system. "mercurial.osutil.getfstype" works as expected. It's hard to mount filesystem on user-space easily. I will add a test for real hardlink support to indirectly test this patch, after turning on real hardlinks support for certain whitelisted filesystems.