title: pkg-config uses wrong prefix
body: <p>I'm installing Aruco 3.0.10 from source with</p>
  
  <pre><code>version="3.0.10"
  pkg="aruco-${version}.zip"
  url="https://netix.dl.sourceforge.net/project/aruco/3.0.0/${pkg}"
  cd `mktemp -d`
  wget -O $pkg $url
  unzip $pkg
  cd aruco-${version}
  mkdir build &amp;&amp; cd build
  cmake ..
  make -j
  sudo make install
  </code></pre>
  
  <p>which gives me <code>/usr/local/lib/pkgconfig/aruco.pc</code>:</p>
  
  <pre><code># pkg-config file for the library
  
  prefix=/usr/local
  exec_prefix=${prefix}
  libdir=${exec_prefix}/lib
  includedir=${prefix}/include
  
  Name: aruco
  Description: ARUCO Library for marker detection
  Version:  3.0.10
  Requires: opencv &gt;= 2.1.0
  Conflicts:
  Libs: -L${libdir} -laruco
  Cflags: -I${includedir}/aruco -I${includedir}
  </code></pre>
  
  <p>However, <code>pkg-config aruco --libs</code> prints</p>
  
  <pre><code>-L/tmp/tmp.gNQGFAaTtz/aruco-3.0.10/build -laruco /usr/lib/x86_64-linux-gnu/libopencv_calib3d.so -lopencv_calib3d /usr/lib/x86_64-linux-gnu/libopencv_contrib.so -lopencv_contrib /usr/lib/x86_64-linux-gnu/libopencv_core.so -lopencv_core /usr/lib/x86_64-linux-gnu/libopencv_features2d.so -lopencv_features2d /usr/lib/x86_64-linux-gnu/libopencv_flann.so -lopencv_flann /usr/lib/x86_64-linux-gnu/libopencv_gpu.so -lopencv_gpu /usr/lib/x86_64-linux-gnu/libopencv_highgui.so -lopencv_highgui /usr/lib/x86_64-linux-gnu/libopencv_imgproc.so -lopencv_imgproc /usr/lib/x86_64-linux-gnu/libopencv_legacy.so -lopencv_legacy /usr/lib/x86_64-linux-gnu/libopencv_ml.so -lopencv_ml /usr/lib/x86_64-linux-gnu/libopencv_objdetect.so -lopencv_objdetect /usr/lib/x86_64-linux-gnu/libopencv_ocl.so -lopencv_ocl /usr/lib/x86_64-linux-gnu/libopencv_photo.so -lopencv_photo /usr/lib/x86_64-linux-gnu/libopencv_stitching.so -lopencv_stitching /usr/lib/x86_64-linux-gnu/libopencv_superres.so -lopencv_superres /usr/lib/x86_64-linux-gnu/libopencv_ts.so -lopencv_ts /usr/lib/x86_64-linux-gnu/libopencv_video.so -lopencv_video /usr/lib/x86_64-linux-gnu/libopencv_videostab.so -lopencv_videostab
  </code></pre>
  
  <p>So it doesn't seem to use the <code>prefix=/usr/local</code>, but rather the build directory. Since this is a temp folder, this is not going to work for long. How can I fix this?</p>