let configure figure out if we have the header files

git-svn-id: http://svn.freeswitch.org/svn/freeswitch/trunk@8889 d0543943-73ff-0310-b7d9-9358b9ac24b2

src/include/private/switch_core_pvt.h

@@ -60,6 +60,10 @@ typedef apr_os_thread_t switch_thread_id_t;
 #include <sys/mman.h>
 #endif
 
+#ifdef HAVE_NETDB_H
+#include <netdb.h>
+#endif
+
 #ifndef WIN32
 /* setuid, setgid */
 #include <unistd.h>