add minimal winsock->BSD networking header shims

also add license header to existing shims

include/sys/ioctl.h

@@ -0,0 +1,11 @@
+/*
+ * Public domain
+ * sys/ioctl.h compatibility shim
+ */
+
+#ifndef _WIN32
+#include_next <sys/ioctl.h>
+#else
+#include <win32netcompat.h>
+#define ioctl(fd, type, arg) ioctlsocket(fd, type, arg)
+#endif