Function snprintf

src/os/strings.h:25–34

	#if _MSC_VER < 1900
	static int snprintf(char *str, size_t size, const char *format, ...)
	{
		va_list ap;
		int ret;

		va_start(ap, format);
		ret = vsnprintf(str, size, format, ap);
		va_end(ap);
		return ret;
	}

	/**
	 * Almost POSIX compliant implementation of \c vsnprintf for VC compiler.