It's sort of a nonstandard punctuation thing, especially on Twitter, where characters are limited and space-saving measures like single spaces after periods are standard.
Blue Origin technically went into space for about ~30 seconds. The space officially starts at the Karman line (100 kilometers) and they reached 100.5 kilometers for a split second.
Interesting article that exposes some problems of C, that some take for granted or ignore.
However the arguing that C is not Turing complete after you take away the IO and limit yourself on an non-abstract machine is silly. C can simulate any Turing machine limited by the same previously mentioned rules and the same holds if you remove those rules for both systems, not just for one.
A complete tutorial on compiling Quake is already online: https://www.youtube.com/watch?v=2mKd3tPr9As