Merge of r4948, r4949, r4964, r4973, r5011: variables. *) Allow the complex value to be defined as an empty string. This makes conversion from strings to complex values possible without the loss of functionality. *) The "auth_basic" directive gained support of variables. *) Fixed variable syntax checking in "set", "geo", "limit_conn_zone", and "perl_set" directives. *) Added checks that disallow adding a variable with an empty name. Added variable name syntax checks to "geo" and "map" directives. *) Variables $pipe, $request_length, $time_iso8601, and $time_local. Log module counterparts are preserved for efficiency. Based on patch by Kiril Kalchev.

--- a/src/http/modules/ngx_http_sub_filter_module.c
+++ b/src/http/modules/ngx_http_sub_filter_module.c
@@ -627,7 +627,7 @@ ngx_http_sub_filter(ngx_conf_t *cf, ngx_
     ngx_str_t                         *value;
     ngx_http_compile_complex_value_t   ccv;
 
-    if (slcf->match.len) {
+    if (slcf->match.data) {
         return "is duplicate";
     }
 
@@ -687,7 +687,7 @@ ngx_http_sub_merge_conf(ngx_conf_t *cf, 
     ngx_conf_merge_value(conf->once, prev->once, 1);
     ngx_conf_merge_str_value(conf->match, prev->match, "");
 
-    if (conf->value.value.len == 0) {
+    if (conf->value.value.data == NULL) {
         conf->value = prev->value;
     }