Merge pull request #7 from fdik/mac_merge

libetpan with Xcode 12

configure.ac

@@ -564,9 +564,10 @@ if test "x$enable_ipv6" != "xno"; then
     dnl check for getaddrinfo and freeaddrinfo function presence
     for func in "getaddrinfo" "freeaddrinfo"; do
       AC_MSG_CHECKING([for $func])
-      AC_TRY_LINK([], [$func();], 
-                      [func_present=yes], 
-                      [func_present=no])
+      AC_TRY_LINK([#include <netdb.h> ],
+                  [$func;],
+                  [func_present=yes],
+                  [func_present=no])
       AC_MSG_RESULT($func_present)
 
       if test "x$func_present" = "xno"; then