Force binary mode for output zip files on Windows.

According to Pierre Joye, Windows in some environments per default
creates text files (ignoring the "b" in the fdopen mode argument).

--HG--
branch : HEAD
diff --git a/lib/zip_close.c b/lib/zip_close.c
index 02aba65..c8e44a2 100644
--- a/lib/zip_close.c
+++ b/lib/zip_close.c
@@ -596,6 +596,14 @@
 	return NULL;
     }
 
+#ifdef _WIN32
+    /*
+      According to Pierre Joye, Windows in some environments per
+      default creates text files, so force binary mode.
+    */
+    _setmode(_fileno(tfp), _O_BINARY );
+#endif
+
     *outp = tfp;
     return temp;
 }