Minor reorganisation and a few bug fixes.

diff --git a/tools/winapi/winapi_extract b/tools/winapi/winapi_extract
index 3680bdb..de72ae0 100755
--- a/tools/winapi/winapi_extract
+++ b/tools/winapi/winapi_extract
@@ -10,7 +10,7 @@
 }
 
 use config qw(
-    &file_type &file_skip &files_skip &get_spec_files
+    &file_type &files_skip &files_filter &get_spec_files
     $current_dir $wine_dir $winapi_dir $winapi_check_dir
 );
 use modules;