title: Header files with prefix in CMake project
body: <p>I have set up a CMake project whose directory structure looks as follows:</p>
  
  <pre><code>src/
  --CMakeLists.txt
  --libA/
  ----CMakeLists.txt
  ----foo.h
  ----foo.cpp
  --main/
  ----CMakeLists.txt
  ----main.cpp
  </code></pre>
  
  <p><code>src/CMakeLists.txt</code> uses  <code>add_subdirectory</code> to pull in <code>libA</code> and <code>main</code>. <code>libA/CMakeLists.txt</code> uses <code>add_library</code> to define a library called <code>libA</code>, which exports <code>foo.h</code> via <code>target_include_directories</code>. If I now link against <code>libA</code> in <code>main</code> using <code>target_link_library</code>, I can include <code>foo.h</code> via <code>#include &lt;foo.h&gt;</code> in <code>main.cpp</code>. </p>
  
  <p><strong>Question:</strong> Is it possible to provide the public interface of <code>libA</code> with a prefix, so that I can (and have to) write <code>#include &lt;libA/foo.h&gt;</code> in <code>main.cpp</code> instead?</p>