surrounded modifications to the "check" target with tests for LIB_PROTO_MUTATOR_TESTING
diff --git a/examples/expat/CMakeLists.txt b/examples/expat/CMakeLists.txt
index f2031f5..aa5ee4c 100644
--- a/examples/expat/CMakeLists.txt
+++ b/examples/expat/CMakeLists.txt
@@ -34,4 +34,6 @@
                       ${GTEST_BOTH_LIBRARIES}
                       ${CMAKE_THREAD_LIBS_INIT})
 add_test(test.expat_example_test expat_example_test --gtest_color=yes AUTO)
-add_dependencies(check expat_example_test)
+if(LIB_PROTO_MUTATOR_TESTING)
+  add_dependencies(check expat_example_test)
+endif()
\ No newline at end of file