node: provide snprintf implementation on windows

_snprintf() doesn't zero-terminate the buffer on overflow.

src/node_internals.h

@@ -27,7 +27,17 @@
 namespace node {
 
 #ifdef _WIN32
-# define snprintf _snprintf
+// emulate snprintf() on windows, _snprintf() doesn't zero-terminate the buffer
+// on overflow...
+#include <stdarg.h>
+inline static int snprintf(char* buf, unsigned int len, const char* fmt, ...) {
+  va_list ap;
+  va_start(ap, fmt);
+  int n = _vsprintf_p(buf, len, fmt, ap);
+  if (len) buf[len - 1] = '\0';
+  va_end(ap);
+  return n;
+}
 #endif
 
 #ifndef offset_of