don't use before it's actually known.

Index: config.h.in
--- config.h.in.orig
+++ config.h.in
@@ -1,9 +1,6 @@
 /* config.h.in.  Generated from configure.in by autoheader.  */
 
 
-   using namespace std;
-
-
 /* Define to 1 if you have the <algorithm> header file. */
 #undef HAVE_ALGORITHM