fixe int32_t definition for VC11

int32_t is nowhere in msvc, so the version check could be even removed
diff --git a/json_inttypes.h b/json_inttypes.h
index 2f84ade..bfe1060 100644
--- a/json_inttypes.h
+++ b/json_inttypes.h
@@ -4,7 +4,7 @@
 
 #include "json_config.h"
 
-#if defined(_MSC_VER) && _MSC_VER < 1700
+#if defined(_MSC_VER) && _MSC_VER =< 1700
 
 /* Anything less than Visual Studio C++ 10 is missing stdint.h and inttypes.h */
 typedef __int32 int32_t;