[gtkmm-documentation] input example: Change Glib::IOCondition::IN to Glib::IOCondition::IO_IN

[Kjell Ahlstedt <kjellahl src gnome org>]

commit ebae623ce23bbff61988b70b0e9ad70d3feab8af
Author: Kjell Ahlstedt <kjellahlstedt gmail com>
Date:   Thu Sep 7 07:56:44 2017 +0200

    input example: Change Glib::IOCondition::IN to Glib::IOCondition::IO_IN
    
    Bug 786717

 examples/book/input/main.cc |    4 ++--
 1 files changed, 2 insertions(+), 2 deletions(-)
---
diff --git a/examples/book/input/main.cc b/examples/book/input/main.cc
index 29543a5..dc4b2ef 100644
--- a/examples/book/input/main.cc
+++ b/examples/book/input/main.cc
@@ -29,7 +29,7 @@ Glib::RefPtr<Glib::IOChannel> iochannel;
 // and quit the program if the message was 'Q'.
 bool MyCallback(Glib::IOCondition io_condition)
 {
-  if ((io_condition & Glib::IOCondition::IN) != Glib::IOCondition::IN) {
+  if ((io_condition & Glib::IOCondition::IO_IN) != Glib::IOCondition::IO_IN) {
     std::cerr << "Invalid fifo response" << std::endl;
   }
   else {
@@ -76,7 +76,7 @@ int main(int argc, char *argv[])
   }
 
   // connect the signal handler
-  Glib::signal_io().connect(sigc::ptr_fun(MyCallback), read_fd, Glib::IOCondition::IN);
+  Glib::signal_io().connect(sigc::ptr_fun(MyCallback), read_fd, Glib::IOCondition::IO_IN);
 
   // Creates a iochannel from the file descriptor
   iochannel = Glib::IOChannel::create_from_fd(read_fd);