lwip: define LWIP_POSIX_SOCKETS_IO_NAMES as zero (#457)

This patch gets the newlib standard stream descriptors playing well with the
lwip socket descriptors and the spiffs file descriptors. The LWIP_SOCKET_OFFSET
is now defined to be 3, rather than zero, to avoid clashing with the standard
stream descriptors, and the SPIFFS_FILEHDL_OFFSET is bumped up to start after
the lwip descriptors.

lwip/include/arch/cc.h

@@ -39,6 +39,7 @@
 #include <sys/time.h>
 #include <sys/errno.h>
 #include <esp/hwrand.h>
+#include <fcntl.h>
 
 struct ip4_addr;
 struct esf_buf;

lwip/include/lwipopts.h

@@ -144,6 +144,15 @@
    ------------------------------------------------
 */
 
+/**
+ * MEMP_NUM_NETCONN: the number of struct netconns.
+ * (only needed if you use the sequential API, like api_lib.c)
+ * This also sets the number of lwip socket descriptors.
+ */
+#ifndef MEMP_NUM_NETCONN
+#define MEMP_NUM_NETCONN                12
+#endif
+
 /*
    --------------------------------
    ---------- ARP options -------
@@ -549,6 +558,25 @@
    ---------- Socket options ----------
    ------------------------------------
 */
+
+/**
+ * LWIP_POSIX_SOCKETS_IO_NAMES==1: Enable POSIX-style sockets functions names.
+ * Disable this option if you use a POSIX operating system that uses the same
+ * names (read, write & close). (only used if you use sockets.c)
+ */
+#define LWIP_POSIX_SOCKETS_IO_NAMES     0
+
+/**
+ * LWIP_SOCKET_OFFSET==n: Increases the file descriptor number created by LwIP with n.
+ * This can be useful when there are multiple APIs which create file descriptors.
+ * When they all start with a different offset and you won't make them overlap you can
+ * re implement read/write/close/ioctl/fnctl to send the requested action to the right
+ * library (sharing select will need more work though).
+ */
+#ifndef LWIP_SOCKET_OFFSET
+#define LWIP_SOCKET_OFFSET              3
+#endif
+
 /**
  * LWIP_SO_SNDTIMEO==1: Enable send timeout for sockets/netconns and
  * SO_SNDTIMEO processing.

lwip/lwip

@@ -1 +1 @@
-Subproject commit 74676d46f0bc5ed82515f8e247008b7c45ec6cf6
+Subproject commit f372198834caf642c4b2d29d98fc1e120e3ce2b2