linux-user: Implement ioctl cmd TIOCGPTPEER

With glibc 2.27 the openpty function prefers the TIOCGPTPEER ioctl.

Signed-off-by: Andreas Schwab <schwab@suse.de>
Reviewed-by: Laurent Vivier <laurent@vivier.eu>
Message-Id: <mvmbmhdosb9.fsf_-_@suse.de>
Signed-off-by: Laurent Vivier <laurent@vivier.eu>
diff --git a/linux-user/syscall.c b/linux-user/syscall.c
index 82b35a6..effc3a0 100644
--- a/linux-user/syscall.c
+++ b/linux-user/syscall.c
@@ -5636,6 +5636,15 @@
     return get_errno(safe_ioctl(fd, ie->host_cmd, sig));
 }
 
+#ifdef TIOCGPTPEER
+static abi_long do_ioctl_tiocgptpeer(const IOCTLEntry *ie, uint8_t *buf_temp,
+                                     int fd, int cmd, abi_long arg)
+{
+    int flags = target_to_host_bitmask(arg, fcntl_flags_tbl);
+    return get_errno(safe_ioctl(fd, ie->host_cmd, flags));
+}
+#endif
+
 static IOCTLEntry ioctl_entries[] = {
 #define IOCTL(cmd, access, ...) \
     { TARGET_ ## cmd, cmd, #cmd, access, 0, {  __VA_ARGS__ } },