newlib: Fix a case in FD_ISSET macro when n==-1
@@ -34,4 +34,17 @@ int select(int nfds, fd_set *readfds, fd_set *writefds, fd_set *errorfds, struct
#endif // fd_set
+#if defined(FD_ISSET) || defined(FD_SET) || defined(FD_CLR)
+#undef FD_SET
+#undef FD_CLR
+#undef FD_ISSET
+
+#define __FD_SAFE_SET(n, code) do { if ((unsigned)(n) < FD_SETSIZE) { code; } } while(0)
+#define __FD_SAFE_GET(n, code) (((unsigned)(n) < FD_SETSIZE) ? (code) : 0)
+
+#define FD_SET(n, p) __FD_SAFE_SET(n, ((p)->fds_bits[(n) / NFDBITS] |= (1L << ((n) % NFDBITS))))
+#define FD_CLR(n, p) __FD_SAFE_SET(n, ((p)->fds_bits[(n) / NFDBITS] &= ~(1L << ((n) % NFDBITS))))
+#define FD_ISSET(n, p) __FD_SAFE_GET(n, ((p)->fds_bits[(n) / NFDBITS] & (1L << ((n) % NFDBITS))))
+#endif // FD_ISSET || FD_SET || FD_CLR
+
#endif //__ESP_SYS_SELECT_H__
