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

diff --git a/configure.ac b/configure.ac
index c844eb1..b5beb08 100644
--- a/configure.ac
+++ b/configure.ac
@@ -2782,9 +2782,7 @@
 AC_MSG_CHECKING(for uuid_enc_be)
 AC_COMPILE_IFELSE([AC_LANG_PROGRAM([[#include <uuid.h>]], [[
 #ifndef uuid_enc_be
-uuid_t uuid;
-unsigned char buf[sizeof(uuid)];
-uuid_enc_be(buf, &uuid);
+void *x = uuid_enc_be
 #endif
 ]])],
   [AC_DEFINE(HAVE_UUID_ENC_BE, 1, Define if uuid_enc_be() exists.)