* configure.ac (HAVE_BROKEN_TTYNAME): New ac_define set for Android
systems.
* common/util.h (gnupg_ttyname): New macro.  Change all callers of
ttyname to use this macro instead.
(ttyname) [W32]: Rename to _gnupg_ttyname and use also if
HAVE_BROKEN_TTYNAME is defined.
* common/simple-pwquery.c (agent_send_all_options): Keep on using
ttyname unless HAVE_BROKEN_TTYNAME is set.  This is because this file
may be used standalone.