Add modulemap for gRPC core
diff --git a/gRPC-Core.podspec b/gRPC-Core.podspec
index c924ab3..54e652e 100644
--- a/gRPC-Core.podspec
+++ b/gRPC-Core.podspec
@@ -56,6 +56,8 @@
   s.module_name = name
   s.header_dir = name
 
+  s.module_map = 'include/grpc/module.modulemap'
+
   s.source_files = 'src/core/lib/profiling/timers.h',
                    'src/core/lib/support/backoff.h',
                    'src/core/lib/support/block_annotate.h',