Fixes for OSX

[beadon]

Not a complete fix, but an obvious fix for the missing OSX dependency.

[beadon]

Added a fix to find the eye-fi device on a MacOS system. Not special sauce, borrowed the logic from the Linux version and hacked away.

note the md5 change in this commit too , this appeared to need to be dereferenced correctly.

[bjanssen]

@beadon , did you get this to work (and on what machine)?
I tried with an M3 on Sonoma and an x86 on Sequoia and both get stuck in the read_from function (goto retry loop) giving
fd_flush(3) was unsuccessful(0), retrying (retry count)...
perror tells me Bad file descriptor.

Your code does compile on my macs, in contrast to the original master and the fork/PR by @btb .

Update: found an old version of @btb 's fork on my HD (with some minor edits). It was probably compiled on snow leopard. The binary does work on my Sequoia x86 machine.