Fixed config load for MSVC.

src/3rdparty/jansson/dump.c

@@ -19,10 +19,16 @@
 #include <stdlib.h>
 #include <string.h>
 #include <assert.h>
-#ifdef HAVE_UNISTD_H
+
+#if defined(HAVE_UNISTD_H) && !defined(_MSC_VER)
 #include <unistd.h>
 #endif
 
+#if defined(_MSC_VER)
+#include <BaseTsd.h>
+typedef SSIZE_T ssize_t;
+#endif
+
 #include "jansson.h"
 #include "strbuffer.h"
 #include "utf.h"