--- a/t/lex-clean-cxx.sh	2013-06-09 11:31:22.000000000 +0200
+++ b/t/lex-clean-cxx.sh	2013-10-22 13:48:48.000000000 +0200
@@ -70,9 +70,11 @@
 cat > mainfoo.cc << 'END'
 // This file should contain valid C++ but invalid C.
 using namespace std;
+
+extern "C" int yylex (void);
+
 int main (int argc, char **argv)
 {
-  extern int yylex (void);
   return yylex ();
 }
 END