[gimp/gtk3-port: 250/391] configure.ac: don't define GDK/GTK_MULTIHEAD_SAFE, they are gone

[Michael Natterer <mitch src gnome org>]

commit e0d1d4900cce1b6044346829a9df29b8e420cad5
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 d7e3e6c..223b3c0 100644
--- a/configure.ac
+++ b/configure.ac
@@ -2392,13 +2392,6 @@ if test "x$have_pango_1_32" != "xyes"; then
 fi
 
 
-############################
-# Require multihead safe API
-############################
-
-CPPFLAGS="${CPPFLAGS} -DGDK_MULTIHEAD_SAFE -DGTK_MULTIHEAD_SAFE"
-
-
 ##################
 # configure output
 ##################