Merge branch 'bugfix/newlib_FD_ISSET_v4.2' into 'release/v4.2'

newlib: Fix a case in FD_ISSET macro when n==-1 (v4.2)

See merge request espressif/esp-idf!13691

components/newlib/platform_include/sys/select.h

@@ -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__