Resolve -Wundef triggering on GTEST_CREATE_SHARED_LIBRARY and GTEST_LINKED_AS_SHARED_LIBRARY with shared libraries in GoogleTest

Fixes: #4372
PiperOrigin-RevId: 568327612
Change-Id: Ifc47f1a2a2648c29858a22966331557cc928cc47

Author: Abseil Team

googletest/include/gtest/internal/gtest-port.h

@@ -845,9 +845,9 @@ typedef struct _RTL_CRITICAL_SECTION GTEST_CRITICAL_SECTION;
 #ifndef GTEST_API_
 
 #ifdef _MSC_VER
-#if GTEST_LINKED_AS_SHARED_LIBRARY
+#if defined(GTEST_LINKED_AS_SHARED_LIBRARY) && GTEST_LINKED_AS_SHARED_LIBRARY
 #define GTEST_API_ __declspec(dllimport)
-#elif GTEST_CREATE_SHARED_LIBRARY
+#elif defined(GTEST_CREATE_SHARED_LIBRARY) && GTEST_CREATE_SHARED_LIBRARY
 #define GTEST_API_ __declspec(dllexport)
 #endif
 #elif GTEST_HAVE_ATTRIBUTE_(visibility)