Compile and link core tests with libuv
diff --git a/gRPC-Core.podspec b/gRPC-Core.podspec
index 479045d..7ce0a0d 100644
--- a/gRPC-Core.podspec
+++ b/gRPC-Core.podspec
@@ -439,6 +439,7 @@
                       'src/core/lib/iomgr/combiner.c',
                       'src/core/lib/iomgr/endpoint.c',
                       'src/core/lib/iomgr/endpoint_pair_posix.c',
+                      'src/core/lib/iomgr/endpoint_pair_uv.c',
                       'src/core/lib/iomgr/endpoint_pair_windows.c',
                       'src/core/lib/iomgr/error.c',
                       'src/core/lib/iomgr/ev_epoll_linux.c',