- API files update.
- Minor improvement and bug fixes.

diff --git a/tools/winapi_check/modules.pm b/tools/winapi_check/modules.pm
index 82ac2e4..daa91ae 100644
--- a/tools/winapi_check/modules.pm
+++ b/tools/winapi_check/modules.pm
@@ -44,6 +44,10 @@
     &Exporter::import(@_);
     $Exporter::ExportLevel--;
 
+    if (defined($modules)) {
+	return;
+    }
+
     $modules = 'modules'->new;
 }