diff --git a/Zend/Zend.m4 b/Zend/Zend.m4
index d64d5807247..9da6a53e4ce 100644
--- a/Zend/Zend.m4
+++ b/Zend/Zend.m4
@@ -183,6 +183,7 @@ dnl extra check to avoid C++ preprocessor testing if in non-ZTS mode
 		
 if test "$ZEND_EXPERIMENTAL_ZTS" = "yes"; then
 AC_PROG_CXX		
+AC_PROG_CXXCPP
 AC_LANG_CPLUSPLUS
 AC_CHECK_HEADER(stdiostream.h, [ AC_DEFINE(HAVE_STDIOSTREAM_H, [], Whether you have stdiostream.h) ])