-In Termux these are implemented in the libutil package to support android-21.
-
diff -u -r /home/fornwall/lib/android-ndk/sysroot/usr/include/pty.h ./usr/include/pty.h
---- /home/fornwall/lib/android-ndk/sysroot/usr/include/pty.h 2017-06-20 17:41:56.000000000 +0200
-+++ ./usr/include/pty.h 2017-07-02 11:42:39.244882732 +0200
-@@ -37,10 +37,8 @@
- __BEGIN_DECLS
+--- /home/fornwall/lib/android-ndk/sysroot/usr/include/pty.h 2017-11-09 09:57:12.000000000 +0100
++++ ./usr/include/pty.h 2017-11-15 11:52:53.115077179 +0100
+@@ -36,12 +36,9 @@
+ __BEGIN_DECLS
+-
-#if __ANDROID_API__ >= 23
--int openpty(int*, int*, char*, const struct termios*, const struct winsize*) __INTRODUCED_IN(23);
--int forkpty(int*, char*, const struct termios*, const struct winsize*) __INTRODUCED_IN(23);
+-int openpty(int* __master_fd, int* __slave_fd, char* __slave_name, const struct termios* __termios_ptr, const struct winsize* __winsize_ptr) __INTRODUCED_IN(23);
+-int forkpty(int* __master_fd, char* __slave_name, const struct termios* __termios_ptr, const struct winsize* __winsize_ptr) __INTRODUCED_IN(23);
-#endif /* __ANDROID_API__ >= 23 */
-+int openpty(int*, int*, char*, const struct termios*, const struct winsize*);
-+int forkpty(int*, char*, const struct termios*, const struct winsize*);
-
+-
++/* In Termux these are implemented in the libutil package to support android-21. */
++int openpty(int* __master_fd, int* __slave_fd, char* __slave_name, const struct termios* __termios_ptr, const struct winsize* __winsize_ptr);
++int forkpty(int* __master_fd, char* __slave_name, const struct termios* __termios_ptr, const struct winsize* __winsize_ptr);
__END_DECLS
+