detect when compiling with MINGW32 to avoid typedef redefinition error on

C99 size types

Author: pijyoi

include/czmq_prelude.h

@@ -398,11 +398,13 @@ typedef unsigned int    qbyte;          //  Quad byte = 32 bits
 #   define vsnprintf _vsnprintf
     typedef unsigned long ulong;
     typedef unsigned int  uint;
+#   if (!defined (__MINGW32__)) 
     typedef __int32 int32_t;
     typedef __int64 int64_t;
     typedef unsigned __int32 uint32_t;
     typedef unsigned __int64 uint64_t;
     typedef long ssize_t;
+#   endif 
 #elif (defined (__APPLE__))
     typedef unsigned long ulong;
     typedef unsigned int uint;