1 In Termux login_tty() is implemented in the libutil package to support android-21.
3 diff -u -r /home/fornwall/lib/android-ndk/sysroot/usr/include/utmp.h ./usr/include/utmp.h
4 --- /home/fornwall/lib/android-ndk/sysroot/usr/include/utmp.h 2017-06-20 17:41:56.000000000 +0200
5 +++ ./usr/include/utmp.h 2017-07-10 09:47:42.422659110 +0200
7 struct utmp* getutent(void);
11 -#if __ANDROID_API__ >= 23
12 -int login_tty(int) __INTRODUCED_IN(23);
13 -#endif /* __ANDROID_API__ >= 23 */