Fix compilation using MSVC 2008: its <algorithm> defines wrong min/max without NOMINMAX

Visual Studio 2008 compiler defines min/max as macros in its <algorithm> even if <windows.h> is not included at all. This patch defines NOMINMAX to remove these macros and fix compilation on Visual Studio 2008.

src/encoder.hpp

@@ -22,6 +22,12 @@
 #ifndef __ZMQ_ENCODER_HPP_INCLUDED__
 #define __ZMQ_ENCODER_HPP_INCLUDED__
 
+#if defined(_MSC_VER)
+#ifndef NOMINMAX
+#define NOMINMAX
+#endif
+#endif
+
 #include <stddef.h>
 #include <string.h>
 #include <stdlib.h>