travis: Remove libtxc_dxtn from the build

Reviewed-by: Nicolai Hähnle <nicolai.haehnle@amd.com>
Reviewed-by: Emil Velikov <emil.velikov@collabora.com>

.travis.yml

@@ -20,7 +20,6 @@ env:
     - XCBPROTO_VERSION=xcb-proto-1.11
     - LIBXCB_VERSION=libxcb-1.11
     - LIBXSHMFENCE_VERSION=libxshmfence-1.2
-    - LIBTXC_DXTN_VERSION=libtxc_dxtn-1.0.1
     - LIBVDPAU_VERSION=libvdpau-1.1
     - LIBVA_VERSION=libva-1.6.2
     - LIBWAYLAND_VERSION=wayland-1.11.1
@@ -442,19 +441,6 @@ install:
   - tar -jxvf $LIBXSHMFENCE_VERSION.tar.bz2
   - (cd $LIBXSHMFENCE_VERSION && ./configure --prefix=$HOME/prefix && make install)
 
-  # libtxc-dxtn uses the patented S3 Texture Compression
-  # algorithm. Therefore, we don't want to use this library but it is
-  # still possible through setting the USE_TXC_DXTN variable to yes in
-  # the travis web UI.
-  #
-  # According to Wikipedia, the patent expires on October 2, 2017:
-  # https://en.wikipedia.org/wiki/S3_Texture_Compression#Patent
-  - if test "x$USE_TXC_DXTN" = xyes; then
-      wget https://people.freedesktop.org/~cbrill/libtxc_dxtn/$LIBTXC_DXTN_VERSION.tar.bz2;
-      tar -jxvf $LIBTXC_DXTN_VERSION.tar.bz2;
-      (cd $LIBTXC_DXTN_VERSION && ./configure --prefix=$HOME/prefix && make install);
-    fi
-
   - wget http://people.freedesktop.org/~aplattner/vdpau/$LIBVDPAU_VERSION.tar.bz2
   - tar -jxvf $LIBVDPAU_VERSION.tar.bz2
   - (cd $LIBVDPAU_VERSION && ./configure --prefix=$HOME/prefix && make install)