Mayaqua: Replace GNU specific sys/poll.h header with POSIX poll.h
Fixes warning from the musl libc:
warning redirecting incorrect #include <sys/poll.h> to <poll.h>
@@ -157,8 +157,8 @@ int PASCAL WinMain(HINSTANCE hInst, HINSTANCE hPrev, char *CmdLine, int CmdShow)
#ifdef UNIX_SOLARIS
#include <sys/filio.h>
#endif // UNIX_SOLARIS
-#include <sys/poll.h>
#include <sys/resource.h>
+#include <poll.h>
#include <pthread.h>
#ifdef UNIX_LINUX
#include <sys/prctl.h>
