https://bugs.gentoo.org/870667
--- a/acinclude.m4
+++ b/acinclude.m4
@@ -151,4 +151,5 @@
 AC_MSG_CHECKING([if "localhost" resolves])
 AC_TRY_RUN([
+#include <stdlib.h>
 #include <string.h>
 #include <sys/types.h>