travis: build unpaper with cache

.travis.yml

@@ -4,22 +4,28 @@ cache:
     directories:
         - $HOME/.cache/pip
         - $HOME/.ccache
-        - .autoconf
-
+        - tarballs
 
 python:
     - 3.4
 
 before_install:
+    # Ubuntu packages
     - sudo add-apt-repository ppa:evl.ms/precise -y  # for Ghostscript 9.15
     - sudo add-apt-repository ppa:lyrasis/precise-backports -y  # for Tesseract 3.03
     - sudo add-apt-repository ppa:b-eltzner/qpdfview-exp -y  # for QPDF 5
     - sudo apt-get update -qq  # must go after all add-apt-repo
+
+    # pip
     - pip install --upgrade pip
-    - wget -q https://github.com/Flameeyes/unpaper/archive/unpaper-6.1.tar.gz
-    - tar -xvf unpaper-6.1.tar.gz
-    - pushd unpaper-6.1 && autoreconf -i && ./configure --prefix=/usr && make -j && sudo make install && popd
-    - sudo apt-get install -y ghostscript tesseract-ocr tesseract-ocr-deu tesseract-ocr-eng tesseract-ocr-fra qpdf poppler-utils gcc libavformat-dev libavcodec-dev libavutil-dev autoconf automake make pkg-config xsltproc
+
+    # Download, make and install unpaper (using ccache)
+    - mkdir -p tarballs
+    - "[ -f tarballs/unpaper-6.1.tar.xz ] || wget -q https://www.flameeyes.eu/files/unpaper-6.1.tar.xz -O tarballs/unpaper-6.1.tar.xz"
+    - tar -xvf unpaper-6.1.tar.xz
+    - export PATH="/usr/lib/ccache:$PATH"
+    - pushd unpaper-6.1 && ./configure --prefix=/usr && make -j && sudo make install && popd
+    - sudo apt-get install -y ghostscript tesseract-ocr tesseract-ocr-deu tesseract-ocr-eng tesseract-ocr-fra qpdf poppler-utils gcc libavformat-dev libavcodec-dev libavutil-dev make pkg-config xsltproc
 
 install:
     - pip install -r requirements.txt