title: How to include headers in cmake
body: <p>I am trying to introduce myself to cmake. I am using it on windows to produce MinGW Makefiles.</p>
  
  <p>I am used to having a c++ classes header and source file in the same directory, and directories organized by modules.</p>
  
  <p>I would like my cmake configuration to have any cpp be dependent on its corresponding h file. In addition I would like the h and cpp to always exist in same directory.</p>
  
  <p>From what I have read, in cmake, in my add_executable line, I list all the cpp files I want to compile.</p>
  
  <p>If I have src/module1/myclass.cpp listed in my add_executable line, where will cmake look for myclass.h if myclass.cpp lists #include ? Will it make myclass.cpp dependent on myclass.h? This is the behavior I would like.</p>