Use loadable module instead of shared library.

mojo/environment/default_async_waiter_impl.h

Index: mojo/environment/default_async_waiter_impl.h
diff --git a/mojo/environment/default_async_waiter_impl.h b/mojo/environment/default_async_waiter_impl.h
index 5140e35b4c2983fb775e78e236d6bce0afca1361..e697dfc016812c9f01091707d98379e0fb4ca1fb 100644
--- a/mojo/environment/default_async_waiter_impl.h
+++ b/mojo/environment/default_async_waiter_impl.h
@@ -5,13 +5,12 @@
 #ifndef MOJO_ENVIRONMENT_DEFAULT_ASYNC_WAITER_IMPL_H_
 #define MOJO_ENVIRONMENT_DEFAULT_ASYNC_WAITER_IMPL_H_
 
-#include "mojo/environment/mojo_environment_impl_export.h"
 #include "mojo/public/c/environment/async_waiter.h"
 
 namespace mojo {
 namespace internal {
 
-MOJO_ENVIRONMENT_IMPL_EXPORT const MojoAsyncWaiter* GetDefaultAsyncWaiterImpl();
+const MojoAsyncWaiter* GetDefaultAsyncWaiterImpl();
 
 }  // namespace internal
 }  // namespace mojo