title: CMake cannot find Qt5LinguistTools in Docker / Ubuntu 18.04
body: <p>My simple Dockerfile:</p>
  
  <pre><code>FROM ubuntu:18.04
  
  RUN apt update &amp;&amp; apt upgrade -y
  
  RUN apt install build-essential cmake qt5-default -y
  
  RUN apt install qttools5-dev-tools -y
  </code></pre>
  
  <p>When I check <code>linguist</code> inside the container it's there:</p>
  
  <pre><code>root@9087245330a7:/# which linguist
  /usr/bin/linguist
  </code></pre>
  
  <p>...but when I configure my app inside the container:</p>
  
  <pre><code>CMake Error at CMakeLists.txt:72 (find_package):
    By not providing "FindQt5LinguistTools.cmake" in CMAKE_MODULE_PATH this
    project has asked CMake to find a package configuration file provided by
    "Qt5LinguistTools", but CMake did not find one.
  
    Could not find a package configuration file provided by "Qt5LinguistTools"
    (requested version 5.5.1) with any of the following names:
  
      Qt5LinguistToolsConfig.cmake
      qt5linguisttools-config.cmake
  
    Add the installation prefix of "Qt5LinguistTools" to CMAKE_PREFIX_PATH or
    set "Qt5LinguistTools_DIR" to a directory containing one of the above
    files.  If "Qt5LinguistTools" provides a separate development package or
    SDK, be sure it has been installed.
  </code></pre>
  
  <p>What is going on? This works on Ubuntu <code>16.04</code> just fine.</p>