Add a "fork" of musl as //fusl.

fusl/include/termios.h

+#ifndef _TERMIOS_H
+#define _TERMIOS_H
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+#include <features.h>
+
+#define __NEED_pid_t
+
+#include <bits/alltypes.h>
+
+typedef unsigned char cc_t;
+typedef unsigned int speed_t;
+typedef unsigned int tcflag_t;
+
+#define NCCS 32
+
+#include <bits/termios.h>
+
+speed_t cfgetospeed (const struct termios *);
+speed_t cfgetispeed (const struct termios *);
+int cfsetospeed (struct termios *, speed_t);
+int cfsetispeed (struct termios *, speed_t);
+
+int tcgetattr (int, struct termios *);
+int tcsetattr (int, int, const struct termios *);
+
+int tcsendbreak (int, int);
+int tcdrain (int);
+int tcflush (int, int);
+int tcflow (int, int);
+
+pid_t tcgetsid (int);
+
+#if defined(_GNU_SOURCE) || defined(_BSD_SOURCE)
+void cfmakeraw(struct termios *);
+int cfsetspeed(struct termios *, speed_t);
+#endif
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif