MSVC: Disable deprecation warnings for C89 functions

C89 sadly doesn't provide safe alternatives for strcpy, sprintf and the
like.

cJSON.c

@@ -23,6 +23,11 @@
 /* cJSON */
 /* JSON parser in C. */
 
+/* disable warnings about old C89 functions in MSVC */
+#if !defined(_CRT_SECURE_NO_DEPRECATE) && defined(_MSC_VER)
+#define _CRT_SECURE_NO_DEPRECATE
+#endif
+
 #ifdef __GNUC__
 #pragma GCC visibility push(default)
 #endif