Reduce unecessary use of networking headers

The utility configuration header dragged in a number of bsd sockets
and related API as a side effect of setting up the configuration. By
splitting the header and API setup into a separate header only the
small number of places that need the functionality explitly include
it.

content/fetchers.h

@@ -25,7 +25,7 @@
 #ifndef _NETSURF_DESKTOP_FETCHERS_H_
 #define _NETSURF_DESKTOP_FETCHERS_H_
 
-#include "utils/config.h"
+#include "utils/inet.h" /* this is necessary for the fd_set definition */
 #include <libwapcaplet/libwapcaplet.h>
 
 struct nsurl;

content/fetchers/curl.c

@@ -27,7 +27,8 @@
  * The CURL handles are cached in the curl_handle_ring.
  */
 
-#include "utils/config.h"
+/* must come first to ensure winsock2.h vs windows.h ordering issues */
+#include "utils/inet.h"
 
 #include <assert.h>
 #include <errno.h>

content/urldb.c

@@ -96,7 +96,7 @@
 #include <strings.h>
 #include <time.h>
 
-#include "utils/config.h"
+#include "utils/inet.h"
 #include "utils/nsoption.h"
 #include "utils/log.h"
 #include "utils/corestrings.h"

utils/config.h

@@ -61,24 +61,16 @@ char *strchrnul(const char *s, int c);
 
 #define HAVE_SYS_SELECT
 #define HAVE_INETATON
+#define HAVE_POSIX_INET_HEADERS
 #if (defined(_WIN32))
 #undef HAVE_INETATON
 #undef HAVE_SYS_SELECT
-#include <winsock2.h>
-#ifndef EAFNOSUPPORT
-#define EAFNOSUPPORT WSAEAFNOSUPPORT
-#endif
-int inet_aton(const char *cp, struct in_addr *inp);
-#else
-#include <netinet/in.h>
-#include <arpa/inet.h>
-#include <sys/select.h>
+#undef HAVE_POSIX_INET_HEADERS
 #endif
 
 #define HAVE_INETPTON
 #if (defined(_WIN32))
 #undef HAVE_INETPTON
-int inet_pton(int af, const char *src, void *dst);
 #endif
 
 #define HAVE_UTSNAME

utils/inet.h

@@ -0,0 +1,62 @@
+/*
+ * Copyright 2016 Vincent Sanders <vince@netsurf-browser.org>
+ *
+ * This file is part of NetSurf, http://www.netsurf-browser.org/
+ *
+ * NetSurf is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; version 2 of the License.
+ *
+ * NetSurf is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+/**
+ * \file internet structures and defines
+ *
+ * This allows the obtaining of standard bsd sockets and associated
+ * functions in a uniform way despite any oddities in headers and
+ * supported API between OS.
+ *
+ * \note This functionality was previously provided as a side effect of the
+ *  utils config header include.
+ */
+
+#ifndef _NETSURF_UTILS_INET_H_
+#define _NETSURF_UTILS_INET_H_
+
+#include "utils/config.h"
+
+#ifdef HAVE_POSIX_INET_HEADERS
+
+#include <sys/socket.h>
+#include <netinet/in.h>
+#include <arpa/inet.h>
+#include <sys/select.h>
+
+#else
+
+#include <winsock2.h>
+#include <ws2tcpip.h>
+
+#ifndef EAFNOSUPPORT
+#define EAFNOSUPPORT WSAEAFNOSUPPORT
+#endif
+
+#endif
+
+
+#ifndef HAVE_INETATON
+int inet_aton(const char *cp, struct in_addr *inp);
+#endif
+
+#ifndef HAVE_INETPTON
+int inet_pton(int af, const char *src, void *dst);
+#endif
+
+#endif

utils/utils.c

@@ -39,6 +39,7 @@
 #include "utils/messages.h"
 #include "utils/utf8.h"
 #include "utils/time.h"
+#include "utils/inet.h"
 #include "utils/utils.h"
 
 /* exported interface documented in utils/utils.h */