cpp: Deal with systems without AI_ADDRCONFIG (OpenBSD)

git-svn-id: https://svn.apache.org/repos/asf/incubator/thrift/trunk@776926 13f79535-47bb-0310-9956-ffa450edef68
diff --git a/configure.ac b/configure.ac
index 07fa2e3..8fd63d5 100644
--- a/configure.ac
+++ b/configure.ac
@@ -149,6 +149,16 @@
 
 AC_STRUCT_TM
 
+dnl NOTE(dreiss): AI_ADDRCONFIG is not defined on OpenBSD.
+AC_CHECK_DECL([AI_ADDRCONFIG], [],
+              [AC_DEFINE([AI_ADDRCONFIG], 0,
+                         [Define if the AI_ADDRCONFIG symbol is unavailable])],
+              [
+  #include <sys/types.h>
+  #include <sys/socket.h>
+  #include <netdb.h>
+])
+
 AC_FUNC_ALLOCA
 AC_FUNC_MALLOC
 AC_FUNC_MEMCMP