Finally?

.travis.yml

@@ -2,7 +2,11 @@ language: cpp
 compiler: gcc
 sudo: require
 dist: trusty
-cache: ccache
+cache:
+  ccache: true
+  directories:
+  - mpv-build
+  - $HOME/.ccache
 
 before_install:
   - sudo add-apt-repository ppa:beineri/opt-qt-5.10.1-trusty -y

scripts/build-mpv.sh

@@ -6,5 +6,5 @@ echo --enable-libmpv-shared --prefix=/usr  >> mpv_options
 echo --disable-caca --disable-wayland --disable-gl-wayland --disable-libarchive  --disable-zlib  --disable-tv --disable-debug-build --disable-manpage-build --disable-vapoursynth --disable-libsmbclient >> mpv_options
 
 ./rebuild -j`nproc`
-DESTDIR=/usr sudo ./install
+sudo ./install
 cd ..