title: include not found, how to fix with cmake?
body: <p>there my CMakeLists.txt :</p>
  
  <pre><code>cmake_minimum_required( VERSION 2.8 )
  
  set (CMAKE_VERBOSE_MAKEFILE ON)
  
  project( a.out )
  find_package(OpenGL)
  find_package(PkgConfig REQUIRED)
  pkg_search_module(GLFW REQUIRED glfw3)
  pkg_search_module(CEGUI-GL REQUIRED  CEGUI-0-OPENGL)
  pkg_search_module(CEGUI REQUIRED  CEGUI-0)
  
  
  macro( config_project PROJNAME LIBNAME )
  include_directories( ${${LIBNAME}_INCLUDE_DIR} )
  target_link_libraries( ${PROJNAME} ${${LIBNAME}_LIBRARIES} )
  endmacro()
  
  add_definitions(-std=c++11)
  add_executable(a.out src/ConsoleWindow.cc src/camera.cc src/main.cc)
  config_project(a.out OPENGL)
  config_project(a.out GLFW)
  config_project(a.out CEGUI-GL)
  config_project(a.out CEGUI)
  </code></pre>
  
  <p>so, there is <code>PkgConfig</code> for <code>CEGUI-0-OPENGL</code> and <code>CEGUI-0</code>. In <code>CEGUI-0.pc</code> there is:</p>
  
  <pre><code>prefix=/usr
  exec_prefix=${prefix}
  libdir=${prefix}/lib
  includedir=${prefix}/include/cegui-0
  moduledir=${prefix}/lib/cegui-0.8
  datafiles=${prefix}/share/cegui-0
  
  Name: CEGUI-0
  Description: The free GUI library for games and multi-media development.
  Version: 0.8.2
  Libs: -L${libdir} -lCEGUIBase-0
  Cflags: -I${includedir} -I${includedir}/cegui
  </code></pre>
  
  <p>when I run <code>cmake .</code> everything is fine, but in one of my <code>.cc</code> I have :</p>
  
  <pre><code>#include &lt;CEGUI/CEGUI.h&gt;
  </code></pre>
  
  <p>and when I compil the file I got an error like no such file found... but <code>locate</code> return :</p>
  
  <pre><code>/usr/include/cegui-0/CEGUI/CEGUI.h
  </code></pre>
  
  <p>what I'm doing wrong ?</p>