Add ccache and make MPV install to the right location.

.travis.yml

@@ -2,14 +2,7 @@ language: cpp
 compiler: gcc
 sudo: require
 dist: trusty
-
+cache: ccache
-cache:
-  apt: true
-  ccache: true
-  directories:
-    - /var/cache/apt/archives
-  paths:
-    - /var/cache/apt/archives
 
 before_install:
   - sudo add-apt-repository ppa:beineri/opt-qt-5.10.1-trusty -y
@@ -21,6 +14,7 @@ install:
   - source /opt/qt*/bin/qt*-env.sh
 
 script:
+  - export PATH="/usr/lib/ccache:$PATH"
   - bash scripts/build-mpv.sh
   - qmake CONFIG+=release PREFIX=/usr
   - make -j$(nproc)
@@ -48,3 +42,4 @@ branches:
   except:
     - # Do not build tags that we create when we upload to GitHub Releases
     - /^(?i:continuous)/
+

scripts/build-mpv.sh

@@ -2,7 +2,7 @@
 git clone --depth 1 https://github.com/mpv-player/mpv-build
 cd mpv-build
 
-echo --enable-libmpv-shared > mpv_options
+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`