internal/sockets.h: Ensure errno.h included when necessary
@@ -113,6 +113,11 @@ struct servent *PASCAL getservbyname(const char *, const char *);
# include <sys/select.h>
# endif
+# ifdef OPENSSL_SYS_UNIX
+# include <sys/poll.h>
+# include <errno.h>
+# endif
+
# ifndef VMS
# include <sys/ioctl.h>
# else
