atomics: Follow up to r1909321: remaining NEED_ATOMICS_GENERIC64.

git-svn-id: https://svn.apache.org/repos/asf/apr/apr/trunk@1909323 13f79535-47bb-0310-9956-ffa450edef68
diff --git a/atomic/unix/builtins.c b/atomic/unix/builtins.c
index 0a085a0..9a45dfb 100644
--- a/atomic/unix/builtins.c
+++ b/atomic/unix/builtins.c
@@ -27,7 +27,7 @@
 
 APR_DECLARE(apr_status_t) apr_atomic_init(apr_pool_t *p)
 {
-#if defined (NEED_ATOMICS_GENERIC64)
+#if defined (USE_ATOMICS_GENERIC64)
     return apr__atomic_generic64_init(p);
 #else
     return APR_SUCCESS;