diff --git a/src/corelib/global/qsystemdetection.h b/src/corelib/global/qsystemdetection.h
index eb9c4ff04f7..64f9d91ec74 100644
--- a/src/corelib/global/qsystemdetection.h
+++ b/src/corelib/global/qsystemdetection.h
@@ -106,7 +106,7 @@
 #  if defined(WINCE) || defined(_WIN32_WCE)
 #    define Q_OS_WINCE
 #  elif defined(WINAPI_FAMILY)
-#    if WINAPI_FAMILY==WINAPI_FAMILY_PHONE_APP
+#    if defined(WINAPI_FAMILY_PHONE_APP) && WINAPI_FAMILY==WINAPI_FAMILY_PHONE_APP
 #      define Q_OS_WINPHONE
 #      define Q_OS_WINRT
 #    elif WINAPI_FAMILY==WINAPI_FAMILY_APP