diff --git a/build/tools/before_install.sh b/build/tools/before_install.sh
index b640026b75..96286c6a32 100755
--- a/build/tools/before_install.sh
+++ b/build/tools/before_install.sh
@@ -2,7 +2,7 @@
 #
 # This script is used by Travis CI to install the dependencies before building
 # wxWidgets but can also be run by hand if necessary but currently it only
-# works for Ubuntu 12.04 and 14.04 and OS X used by Travis builds.
+# works for Ubuntu versions used by Travis builds.
 
 SUDO=sudo
 
@@ -10,30 +10,37 @@ case $(uname -s) in
     Linux)
         if [ -f /etc/apt/sources.list ]; then
             $SUDO apt-get update
-            case "$wxGTK_VERSION" in
-                3) libgtk_dev=libgtk-3-dev ;;
-                *) libgtk_dev=libgtk2.0-dev;;
-            esac
 
             case "$wxCONFIGURE_FLAGS" in
                 *--with-directfb*) libtoolkit_dev='libdirectfb-dev'         ;;
                 *--with-motif*)    libtoolkit_dev='libmotif-dev libxmu-dev' ;;
                 *--with-qt*)       libtoolkit_dev='qtdeclarative5-dev libqt5opengl5-dev';;
+                *--with-x11*)      ;;
+                *)
+                    case "$wxGTK_VERSION" in
+                        3)  libtoolkit_dev=libgtk-3-dev
+                            extra_deps='libwebkit2gtk-4.0-dev libwebkitgtk-3.0-dev'
+                            ;;
+                        *)  libtoolkit_dev=libgtk2.0-dev
+                            extra_deps='libwebkitgtk-dev'
+                            ;;
+                    esac
+
+                    extra_deps="$extra_deps \
+                            libgstreamermm-1.0-dev libgstreamermm-0.10-dev \
+                            libgstreamer1.0-dev libgstreamer-plugins-base1.0-dev \
+                            libgstreamer0.10-dev libgstreamer-plugins-base0.10-dev \
+                            libglu1-mesa-dev"
             esac
 
-            pgk_check="libgstreamermm-1.0-dev libgstreamermm-0.10-dev \
-                libgstreamer1.0-dev libgstreamer-plugins-base1.0-dev \
-                libgstreamer0.10-dev libgstreamer-plugins-base0.10-dev \
-                libwebkit2gtk-4.0-dev libwebkitgtk-3.0-dev libwebkitgtk-dev \
-                libglu1-mesa-dev libsecret-1-dev libnotify-dev"
-
-            for pkg in $pgk_check; do
+            extra_deps="$extra_deps libsecret-1-dev libnotify-dev"
+            for pkg in $extra_deps; do
                 if $(apt-cache pkgnames | grep -q $pkg) ; then
                     pkg_install="$pkg_install $pkg"
                 fi
             done
 
-            $SUDO apt-get install -y $libgtk_dev $libtoolkit_dev $pkg_install
+            $SUDO apt-get install -y $libtoolkit_dev $pkg_install
         fi
         ;;