Error building with Xcode 9.1, because "system" call has been removed

[idrinkyourcoffee]

Should affect Xcode 9.X generally. The error occurs on line 88 of src/frontend/iosclient.cc (int unused __attribute((unused)) = system( "locale" );).

A quick workaround is to just comment out the line -- its apparent purpose is to output locale information to the user, in case the locale is not UTF-8 native.

I was able to build and run the blink shell successfully under iOS 11.2.2 after making the above change, but I have not tested the mosh functionality yet (ssh works fine).

Keep up the great work on this awesome project! :-)

[idrinkyourcoffee]

Tested mosh, and it works.

Note: Before testing, I rebuilt everything from scratch using Xcode 9.2 (which I needed anyway to deploy to iOS 11.2.2, but I had originally built mosh itself using Xcode 9.1). The results were identical, as expected.