If an employer or prospective employer rescinds their job offer, or makes significant changes to the employment contract, through no fault of your own then you may have reason to engage an attorney and discuss Promissory Estoppel.
I am not a lawyer but it's worth knowing the laws :)
On the plus side, I negotiated to work remotely for a few weeks, due to needing to relocate.
So- I was actually able to work both my current job, and the "new" job without losing time for either job.
So, on the plus side, I didn't lose anything, and got an extra paycheck for a few days. But, man, that would have been really shitty if I had relocated, and THEN got that notification.
As another interesting note, I discovered the other head-dev was only getting compensated 30-40k a year..... for literally managing a world-wide system. He doesn't work there either now.