debian/changelog

+thunar (1.8.0-2) UNRELEASED; urgency=medium
+
+  * d/control: make libthunarx-3-dev depend on gtk-3 dev libs
+
+ -- Yves-Alexis Perez <corsac@debian.org>  Thu, 07 Jun 2018 10:38:40 +0200
+
 thunar (1.8.0-1) experimental; urgency=medium
 
   * New upstream version 1.8.0

debian/control

@@ -33,7 +33,7 @@ Package: libthunarx-3-dev
 Section: libdevel
 Architecture: any
 Depends: libglib2.0-dev,
-         libgtk2.0-dev,
+         libgtk-3-dev,
          libthunarx-3-0 (= ${binary:Version}),
          thunar-data (=${source:Version}),
          ${misc:Depends}