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

fusl/src/misc/pty.c

Index: fusl/src/misc/pty.c
diff --git a/fusl/src/misc/pty.c b/fusl/src/misc/pty.c
new file mode 100644
index 0000000000000000000000000000000000000000..b395d2c09e14f19bad0d7130de8c0a9c1cc14fd4
--- /dev/null
+++ b/fusl/src/misc/pty.c
@@ -0,0 +1,34 @@
+#include <stdlib.h>
+#include <sys/ioctl.h>
+#include <stdio.h>
+#include <fcntl.h>
+#include <errno.h>
+#include "libc.h"
+#include "syscall.h"
+
+int posix_openpt(int flags)
+{
+	return open("/dev/ptmx", flags);
+}
+
+int grantpt(int fd)
+{
+	return 0;
+}
+
+int unlockpt(int fd)
+{
+	int unlock = 0;
+	return ioctl(fd, TIOCSPTLCK, &unlock);
+}
+
+int __ptsname_r(int fd, char *buf, size_t len)
+{
+	int pty, err;
+	if (!buf) len = 0;
+	if ((err = __syscall(SYS_ioctl, fd, TIOCGPTN, &pty))) return -err;
+	if (snprintf(buf, len, "/dev/pts/%d", pty) >= len) return ERANGE;
+	return 0;
+}
+
+weak_alias(__ptsname_r, ptsname_r);