Fix gcc-4.4 testsuite failures (SF#2178663)

--- flex/flex.skl

+++ flex/flex.skl

@@ -219,6 +219,7 @@ m4preproc_include(`flexint.h')

 #include <errno.h>

 #include <cstdlib>

 #include <cstring>

+#include <cstdio>

 /* end standard C++ headers. */

 %endif