Build fails on filesystems that don't support symlinks

[zingaburga]

Likely from #2362

Trying to do a build on a FAT variant filesystem results in an error like:

gyp ERR! stack Error: EPERM: operation not permitted, symlink '/usr/bin/python3' -> '/mnt/drive/project/build/node_gyp_bins/python3'

I couldn't find a switch to disable creating symlinks, so I just edited this condition and it seems to work fine.

It would be nice to either:

• have an option to disable symlink creation
• have the symlink location configurable (which allows it to be, e.g. global)
• if the symlink creation fails, revert to non-symlink behaviour (and maybe print a warning)