Add check for broken symlinks to hacking scripts (#2895)

[jbalsas]

This is a possible fix for #2895.

It adds an additional check for broken symlinks to the current condition.

[peterflynn]

Is there a Windows equivalent to this bug too, or do the .bat files work differently?

[jbalsas]

Yeah, sorry, I forgot to mention that :/ ... I currently don't have access to any windows machine, so I couldn't test it and I can't tell for sure.

From what I saw, the .bat files are checking if exist %1\dev where the .sh were doing if [ -d "${1}/Contents/dev" ]. I'm not quite sure if the condition will fail in windows for broken symlinks, or if it will just check they exist, and I haven't been able to find information about it.

It'd be great if someone could do a quick check, just to be sure.

[gruehle]

Works great! The Windows version was fine as-is.