support "*" in gzip_types, ssi_types, etc

src/http/ngx_http_core_module.c

diff --git a/src/http/ngx_http_core_module.c b/src/http/ngx_http_core_module.c
index b88df33..1766e12 100644
--- a/src/http/ngx_http_core_module.c
+++ b/src/http/ngx_http_core_module.c
@@ -1572,6 +1572,10 @@
     size_t      len;
     ngx_uint_t  i, hash;
 
+    if (types_hash->size == 0) {
+        return (void *) 4;
+    }
+
     if (r->headers_out.content_type.len == 0) {
         return NULL;
     }