Add missing sys/select.h for QNX (closes #158)

POSIX-1.2001 for fd_set. Thanks to spider391Tang.

tests/bandwidth-server-many-up.c

@@ -27,6 +27,7 @@
 #if defined(_WIN32)
 #include <ws2tcpip.h>
 #else
+#include <sys/select.h>
 #include <sys/socket.h>
 #include <netinet/in.h>
 #include <arpa/inet.h>