Set STATIC argument for plugins

Set the STATIC argument when we have 'static' in the qmake
configuration.

Change-Id: Ia8369bbd5ec4cfce0be51f36c61a811d53522729
Reviewed-by: Alexandru Croitor <alexandru.croitor@qt.io>

util/cmake/pro2cmake.py

@@ -2775,6 +2775,9 @@ def write_plugin(cm_fh, scope, *, indent: int = 0) -> str:
     if plugin_class_name:
         extra.append(f"CLASS_NAME {plugin_class_name}")
 
+    if 'static' in scope.get('CONFIG'):
+        extra.append('STATIC')
+
     write_main_part(
         cm_fh,
         plugin_name,