title: Cocoapods/Podspec exclude headers from HEADER_SEARCH_PATHS
body: <p>Some projects I'm working on depend on set of C libraries which I want to manage with wonderful CocoaPods. Each library has private headers like ctype.h, errno.h, string.h deep in the structure. I need them to be copied to Pods/Headers, but NOT flattened in the HEADER_SEARCH_PATHS as it breaks build process.</p>
  
  <p>C-library has the following structure:</p>
  
  <pre><code>mylib/include/mylib.h
  mylib/include/core/errno.h
  ...
  </code></pre>
  
  <p>I want all the headers to be copied to Pod Headers folder, but HEADER_SEARCH_PATHS include "mylib/include" only.</p>
  
  <p>Everything I add using source_files or public_header_files goes to HEADER_SEARCH_PATHS in various Pod .xconfig. If I exclude some headers, they disappear from HEADER_SEARCH_PATHS, but also not copied to Headers.</p>
  
  <p>Any ideas how to solve such problem?</p>