Honor -nomake for examples and demos

Don't build or install examples when they are disabled.

Change-Id: I0da1a1e63899103549a425e14eb64d6f4a10f136
Reviewed-by: Honglei Zhang <honglei.zhang@nokia.com>

qtxmlpatterns.pro

@@ -10,6 +10,9 @@ module_qtxmlpatterns_tools.depends = module_qtxmlpatterns_src
 module_qtxmlpatterns_examples.subdir = examples/xmlpatterns
 module_qtxmlpatterns_examples.target = module-qtxmlpatterns-examples
 module_qtxmlpatterns_examples.depends = module_qtxmlpatterns_src
+!contains(QT_BUILD_PARTS,examples) {
+    module_qtxmlpatterns_examples.CONFIG = no_default_target no_default_install
+}
 
 module_qtxmlpatterns_tests.subdir = tests
 module_qtxmlpatterns_tests.target = module-qtxmlpatterns-tests