Update posix_poll.c: line 49 ppoll-->poll

[drdink]

aligned with posix_poll.h declaration

Wouldn't build until I changed typo.

[Delofon]

pretty sure that's... not really a typo. not only it belongs to a different repo (GLFW which is pulled in as a dependency of raylib) poll and ppoll are two separate syscalls (rax 7 and 271 respectively) with different prototypes (so the way you did it you actually call poll incorrectly, it's better to remove the defined(__linux__) part from the #if directive to use generic code).
Now, the fact that this compilation error is there is nonetheless still odd as ppoll, according to its manpage, is declared in poll.h together with poll. If gcc errors on ppoll with implicit function declaration, then it also should error on poll, but it does not... so this needs to be investigated further (or not... whatever).
I don't think it's inherently a GLFW issue as I really believe uncompileable code wouldn't have hit main GLFW branch, so I guess it's something with the build system then...