[PodTarget] Infer umbrella header

lib/cocoapods/installer/target_installer/pod_target_installer.rb

@@ -270,7 +270,8 @@ module Pod
       end
 
       def create_umbrella_header
-        return super unless custom_module_map
+        inferred_umbrella_header = target.build_headers.root + "#{target.product_module_name}/#{target.product_module_name}.h"
+        return super unless custom_module_map || inferred_umbrella_header.file?
       end
 
       def custom_module_map

lib/cocoapods/target.rb

@@ -140,14 +140,14 @@ module Pod
     #         module map.
     #
     def umbrella_header_path
-      support_files_dir + "#{label}-umbrella.h"
+      support_files_dir + "#{product_module_name}.h"
     end
 
     # @return [Pathname] the absolute path of the LLVM module map file that
     #         defines the module structure for the compiler.
     #
     def module_map_path
-      support_files_dir + "#{label}.modulemap"
+      support_files_dir + "#{product_module_name}.modulemap"
     end
 
     # @return [Pathname] the absolute path of the prefix header file.