package/ci: a shorter way to specify SwiftShader path.

package/ci/travis-desktop-gles.sh

@@ -18,12 +18,9 @@ cd ../..
 mkdir build && cd build
 cmake .. \
     -DCMAKE_CXX_FLAGS="$CMAKE_CXX_FLAGS" \
-    -DCMAKE_PREFIX_PATH="$HOME/deps" \
+    -DCMAKE_PREFIX_PATH="$HOME/deps;$HOME/swiftshader" \
     -DCMAKE_BUILD_TYPE=Debug \
     -DCMAKE_INSTALL_PREFIX=$HOME/deps \
-    -DEGL_LIBRARY=$HOME/swiftshader/lib/libEGL.so \
-    -DOPENGLES2_LIBRARY=$HOME/swiftshader/lib/libGLESv2.so \
-    -DOPENGLES3_LIBRARY=$HOME/swiftshader/lib/libGLESv2.so \
     -DCMAKE_INSTALL_RPATH=$HOME/swiftshader/lib \
     -DTARGET_GLES=ON \
     -DTARGET_GLES2=$TARGET_GLES2 \