title: Define custom module map file in cocoapods Podspec
body: <p>I made a custom <code>module map</code> file to handle the <code>libxml</code> import in a swift project. (<code>non-modular include</code> error)</p>
  <p>It's working great if I do it manually, but <code>cocoapods</code> won't find / resolve the module when I try to <code>pod lint</code> a simple project containing an import from this custom module.</p>
  <p>I tried <code>s.module_map = &quot;module/module.modulemap&quot;</code> along with</p>
  <pre class="lang-rb prettyprint-override"><code>core.xcconfig = {
    'HEADER_SEARCH_PATHS' =&gt; '$(SDKROOT)/usr/include/libxml2 $(SRCROOT)/module $(SDKROOT)/usr/include/libresolv',
    'OTHER_LDFLAGS' =&gt; '&quot;-lxml2&quot;',
    'CLANG_ALLOW_NON_MODULAR_INCLUDES_IN_FRAMEWORK_MODULES' =&gt; 'YES',
    'ENABLE_BITCODE' =&gt; 'NO',
    &quot;SWIFT_INCLUDE_PATHS&quot; =&gt; &quot;$(SRCROOT)/module&quot;
  }
  </code></pre>
  <p>Any help would be appreciated.</p>