[gimp/gtk3-port: 250/274] configure.ac: don't define GDK/GTK_MULTIHEAD_SAFE, they are gone

[Michael Natterer <mitch src gnome org>]

commit c534c9c34e31b5b9ac6631d613ee5d7c70362949
Author: Michael Natterer <mitch gimp org>
Date:   Sun Apr 29 03:53:56 2018 +0200

    configure.ac: don't define GDK/GTK_MULTIHEAD_SAFE, they are gone

 configure.ac |    7 -------
 1 files changed, 0 insertions(+), 7 deletions(-)
---
diff --git a/configure.ac b/configure.ac
index 778879d..57b9097 100644
--- a/configure.ac
+++ b/configure.ac
@@ -2367,13 +2367,6 @@ if test "x$have_pango_1_32" != "xyes"; then
 fi
 
 
-############################
-# Require multihead safe API
-############################
-
-CPPFLAGS="${CPPFLAGS} -DGDK_MULTIHEAD_SAFE -DGTK_MULTIHEAD_SAFE"
-
-
 ##################
 # configure output
 ##################