bpo-32493: Correct test for uuid_enc_be availability in configure.ac. (GH-7511) (GH-7567)

diff --git a/configure b/configure
index f5bea4f..5187c6f 100755
--- a/configure
+++ b/configure
@@ -9632,9 +9632,7 @@
 {
 
 #ifndef uuid_enc_be
-uuid_t uuid;
-unsigned char buf[sizeof(uuid)];
-uuid_enc_be(buf, &uuid);
+void *x = uuid_enc_be
 #endif
 
   ;