lwip: Fix compatibility issues with later versions

The name of the header guard in lwIP's <lwip/opt.h> has changed from
'__LWIP_OPT_H__' to 'LWIP_HDR_OPT_H' (bug #35874 in May 2015).

Other fixes:

- In curl_setup.h, the problem with an old PSDK doesn't apply if lwIP is
used.

- In memdebug.h, the 'socket' should be undefined first due to lwIP's
lwip_socket() macro.

- In curl_addrinfo.c lwIP's getaddrinfo() + freeaddrinfo() macros need
special handling because they were undef'ed in memdebug.h.

- In select.c we can't use preprocessor conditionals inside select if
MSVC and select is a macro, as it is with lwIP.

http://curl.haxx.se/mail/lib-2015-12/0023.html
http://curl.haxx.se/mail/lib-2015-12/0024.html

include/curl/curl.h

@@ -56,7 +56,8 @@
 #include <time.h>
 
 #if defined(WIN32) && !defined(_WIN32_WCE) && !defined(__CYGWIN__)
-#if !(defined(_WINSOCKAPI_) || defined(_WINSOCK_H) || defined(__LWIP_OPT_H__))
+#if !(defined(_WINSOCKAPI_) || defined(_WINSOCK_H) || \
+      defined(__LWIP_OPT_H__) || defined(LWIP_HDR_OPT_H))
 /* The check above prevents the winsock2 inclusion if winsock.h already was
    included, since they can't co-exist without problems */
 #include <winsock2.h>
@@ -112,7 +113,7 @@ typedef void CURL;
 
 #ifndef curl_socket_typedef
 /* socket typedef */
-#if defined(WIN32) && !defined(__LWIP_OPT_H__)
+#if defined(WIN32) && !defined(__LWIP_OPT_H__) && !defined(LWIP_HDR_OPT_H)
 typedef SOCKET curl_socket_t;
 #define CURL_SOCKET_BAD INVALID_SOCKET
 #else

lib/curl_addrinfo.c

@@ -521,7 +521,11 @@ void
 curl_dofreeaddrinfo(struct addrinfo *freethis,
                     int line, const char *source)
 {
+#ifdef USE_LWIPSOCK
+  lwip_freeaddrinfo(freethis);
+#else
   (freeaddrinfo)(freethis);
+#endif
   curl_memlog("ADDR %s:%d freeaddrinfo(%p)\n",
               source, line, (void *)freethis);
 }
@@ -544,7 +548,11 @@ curl_dogetaddrinfo(const char *hostname,
                    struct addrinfo **result,
                    int line, const char *source)
 {
+#ifdef USE_LWIPSOCK
+  int res=lwip_getaddrinfo(hostname, service, hints, result);
+#else
   int res=(getaddrinfo)(hostname, service, hints, result);
+#endif
   if(0 == res)
     /* success */
     curl_memlog("ADDR %s:%d getaddrinfo() = %p\n",

lib/curl_setup.h

@@ -481,9 +481,10 @@
 /*
  * msvc 6.0 requires PSDK in order to have INET6_ADDRSTRLEN
  * defined in ws2tcpip.h as well as to provide IPv6 support.
+ * Does not apply if lwIP is used.
  */
 
-#if defined(_MSC_VER) && !defined(__POCC__)
+#if defined(_MSC_VER) && !defined(__POCC__) && !defined(USE_LWIPSOCK)
 #  if !defined(HAVE_WS2TCPIP_H) || \
      ((_MSC_VER < 1300) && !defined(INET6_ADDRSTRLEN))
 #    undef HAVE_GETADDRINFO_THREADSAFE
@@ -675,7 +676,7 @@ int netware_init(void);
  * Ensure that Winsock and lwIP TCP/IP stacks are not mixed.
  */
 
-#if defined(__LWIP_OPT_H__)
+#if defined(__LWIP_OPT_H__) || defined(LWIP_HDR_OPT_H)
 #  if defined(SOCKET) || \
      defined(USE_WINSOCK) || \
      defined(HAVE_WINSOCK_H) || \

lib/memdebug.h

@@ -103,6 +103,7 @@ CURL_EXTERN int curl_fclose(FILE *file, int line, const char *source);
 #  endif
 #endif
 
+#undef socket
 #define socket(domain,type,protocol)\
  curl_socket(domain, type, protocol, __LINE__, __FILE__)
 #undef accept /* for those with accept as a macro */

lib/select.c

@@ -316,15 +316,15 @@ int Curl_socket_check(curl_socket_t readfd0, /* two sockets to read from */
        curl_socket_t is unsigned in such cases and thus -1 is the largest
        value).
     */
+#ifdef USE_WINSOCK
     r = select((int)maxfd + 1,
-#ifndef USE_WINSOCK
-               &fds_read,
-               &fds_write,
-#else
                fds_read.fd_count ? &fds_read : NULL,
                fds_write.fd_count ? &fds_write : NULL,
-#endif
                &fds_err, ptimeout);
+#else
+    r = select((int)maxfd + 1, &fds_read, &fds_write, &fds_err, ptimeout);
+#endif
+
     if(r != -1)
       break;
     error = SOCKERRNO;
@@ -505,19 +505,19 @@ int Curl_poll(struct pollfd ufds[], unsigned int nfds, int timeout_ms)
       pending_tv.tv_sec = 0;
       pending_tv.tv_usec = 0;
     }
+
+#ifdef USE_WINSOCK
     r = select((int)maxfd + 1,
-#ifndef USE_WINSOCK
-               &fds_read, &fds_write, &fds_err,
-#else
                /* WinSock select() can't handle fd_sets with zero bits set, so
                   don't give it such arguments.  See the comment about this in
                   Curl_check_socket().
                */
                fds_read.fd_count ? &fds_read : NULL,
                fds_write.fd_count ? &fds_write : NULL,
-               fds_err.fd_count ? &fds_err : NULL,
+               fds_err.fd_count ? &fds_err : NULL, ptimeout);
+#else
+    r = select((int)maxfd + 1, &fds_read, &fds_write, &fds_err, ptimeout);
 #endif
-               ptimeout);
     if(r != -1)
       break;
     error = SOCKERRNO;