[PodTargetInstaller] Don't generate an umbrella header when a custom module map is specified.

CHANGELOG.md

@@ -37,6 +37,10 @@ To install release candidates run `[sudo] gem install cocoapods --pre`
   [Samuel Giddins](https://github.com/segiddins)
   [#3502](https://github.com/CocoaPods/CocoaPods/issues/3502)
 
+* Don't generate an umbrella header when a custom module map is specified. This
+  avoids an incomplete module map warning.  
+  [Samuel Giddins](https://github.com/segiddins)
+
 
 ## 0.37.0
 

lib/cocoapods/installer/target_installer/pod_target_installer.rb

@@ -256,10 +256,10 @@ module Pod
       end
 
       def create_module_map
-        return super unless module_map = target.file_accessors.first.module_map
+        return super unless custom_module_map
         path = target.module_map_path
         UI.message "- Copying module map file to #{UI.path(path)}" do
-          FileUtils.cp(module_map, path)
+          FileUtils.cp(custom_module_map, path)
           add_file_to_support_group(path)
 
           native_target.build_configurations.each do |c|
@@ -269,6 +269,14 @@ module Pod
         end
       end
 
+      def create_umbrella_header
+        return super unless custom_module_map
+      end
+
+      def custom_module_map
+        @custom_module_map ||= target.file_accessors.first.module_map
+      end
+
       #-----------------------------------------------------------------------#
     end
   end