fix windows build for once

extern/zlib/contrib/iostream/test.cpp

@@ -0,0 +1,24 @@
+
+#include "zfstream.h"
+
+int main() {
+
+  // Construct a stream object with this filebuffer.  Anything sent
+  // to this stream will go to standard out.
+  gzofstream os( 1, ios::out );
+
+  // This text is getting compressed and sent to stdout.
+  // To prove this, run 'test | zcat'.
+  os << "Hello, Mommy" << endl;
+
+  os << setcompressionlevel( Z_NO_COMPRESSION );
+  os << "hello, hello, hi, ho!" << endl;
+
+  setcompressionlevel( os, Z_DEFAULT_COMPRESSION )
+    << "I'm compressing again" << endl;
+
+  os.close();
+
+  return 0;
+
+}