Convert a config file to build a dynamic module

Resolved FRiCKLE#45

Author: hnakamur

Diff for: config

@@ -15,7 +15,17 @@ if [ "$HTTP_UWSGI" = "YES" ]; then
 fi
 
 ngx_addon_name=ngx_http_cache_purge_module
-HTTP_MODULES="$HTTP_MODULES ngx_http_cache_purge_module"
-NGX_ADDON_SRCS="$NGX_ADDON_SRCS $ngx_addon_dir/ngx_cache_purge_module.c"
+CACHE_PURGE_SRCS="$ngx_addon_dir/ngx_cache_purge_module.c"
+
+if [ -n "$ngx_module_link" ]; then
+    ngx_module_type=HTTP
+    ngx_module_name="$ngx_addon_name"
+    ngx_module_srcs="$CACHE_PURGE_SRCS"
+
+    . auto/module
+else
+    HTTP_MODULES="$HTTP_MODULES $ngx_addon_name"
+    NGX_ADDON_SRCS="$NGX_ADDON_SRCS $CACHE_PURGE_SRCS"
+fi
 
 have=NGX_CACHE_PURGE_MODULE . auto/have