Avoid getrandom@GLIBC_2.25 symbol.

--- old/config.h.in
+++ new/config.h.in
@@ -101,9 +101,6 @@
 /* Define to 1 if you have the `getprotobynumber' function. */
 #undef HAVE_GETPROTOBYNUMBER
 
-/* Define to 1 if you have the `getrandom' function. */
-#undef HAVE_GETRANDOM
-
 /* Define to 1 if you have the `getservbyname' function. */
 #undef HAVE_GETSERVBYNAME