Add network address and socket types

Types and methods for dealing with IPv4 and IPv6 addresses (and UNIX
domain socket addresses under UNIX). This does not include code for
actual socket I/O.

Originally from "gnio". Much of the code was written by Christian
Kellner, Samuel Cormier-Iijima, and Ryan Lortie.

Part of #548466.

configure.in

@@ -954,6 +954,26 @@ AC_CHECK_FUNCS(_NSGetEnviron)
 AC_FUNC_VSNPRINTF_C99
 AC_FUNC_PRINTF_UNIX98
 
+# Internet address families
+if test $glib_native_win32 = yes; then
+  glib_inet_includes=["
+#include <winsock2.h>
+  "]
+else
+  glib_inet_includes=["
+#include <sys/socket.h>
+  "]
+fi
+
+glib_failed=false
+GLIB_CHECK_VALUE(AF_INET, $glib_inet_includes, glib_failed=true)
+GLIB_CHECK_VALUE(AF_INET6, $glib_inet_includes, glib_failed=true)
+# winsock defines this even though it doesn't support it
+GLIB_CHECK_VALUE(AF_UNIX, $glib_inet_includes, glib_failed=true)
+if $glib_failed ; then
+  AC_MSG_ERROR([Could not determine values for AF_INET* constants])
+fi
+
 dnl
 dnl if statfs() takes 2 arguments (Posix) or 4 (Solaris)
 dnl
@@ -2986,6 +3006,10 @@ _______EOF
  */
 typedef $g_pid_type GPid;
 
+#define GLIB_SYSDEF_AF_UNIX $g_af_unix
+#define GLIB_SYSDEF_AF_INET $g_af_inet
+#define GLIB_SYSDEF_AF_INET6 $g_af_inet6
+
 G_END_DECLS
 
 #endif /* GLIBCONFIG_H */
@@ -3272,6 +3296,10 @@ g_pollhup=$glib_cv_value_POLLHUP
 g_pollerr=$glib_cv_value_POLLERR
 g_pollnval=$glib_cv_value_POLLNVAL
 
+g_af_unix=$glib_cv_value_AF_UNIX
+g_af_inet=$glib_cv_value_AF_INET
+g_af_inet6=$glib_cv_value_AF_INET6
+
 g_stack_grows=$glib_cv_stack_grows
 
 g_have_eilseq=$have_eilseq