Add missing async-resolver implementation if we have neither APR threads

nor the Unbound library available.

* src/resolve.c
  (serf__create_resolve_context): Implement when !HAVE_ASYNC_RESOLVER.


git-svn-id: https://svn.apache.org/repos/asf/serf/trunk@1931479 13f79535-47bb-0310-9956-ffa450edef68

Author: brainy

src/resolve.c

@@ -953,6 +953,12 @@ apr_status_t serf__process_async_resolve_results(serf_context_t *ctx)
 
 #else   /* !HAVE_ASYNC_RESOLVER */
 
+/* Internal API */
+apr_status_t serf__create_resolve_context(serf_context_t *ctx)
+{
+    return APR_ENOTIMPL;
+}
+
 /* Internal API */
 apr_status_t serf__process_async_resolve_results(serf_context_t *ctx)
 {