build: make some linkage flags public

Some of the compiler and linker flags need to be used by dependent libraries
which requires making the flags public so that users of the libraries and the
export targets are setup properly.
diff --git a/src/swift/CMakeLists.txt b/src/swift/CMakeLists.txt
index 18a297f..ba987e7 100644
--- a/src/swift/CMakeLists.txt
+++ b/src/swift/CMakeLists.txt
@@ -34,10 +34,12 @@
   "SHELL:-Xcc -I${PROJECT_SOURCE_DIR}")
 set_target_properties(swiftDispatch PROPERTIES
   Swift_MODULE_NAME Dispatch
-  Swift_MODULE_DIRECTORY ${CMAKE_CURRENT_BINARY_DIR}/swift)
+  Swift_MODULE_DIRECTORY ${CMAKE_CURRENT_BINARY_DIR}/swift
+  INTERFACE_INCLUDE_DIRECTORIES ${CMAKE_CURRENT_BINARY_DIR}/swift)
 target_link_libraries(swiftDispatch PRIVATE
   DispatchStubs
-  BlocksRuntime::BlocksRuntime
+  BlocksRuntime::BlocksRuntime)
+target_link_libraries(swiftDispatch PUBLIC
   dispatch)
 add_dependencies(swiftDispatch module-maps)