Workaround for getting libSwiftSyntax built as a dependency in the graph

Author: phausler

lib/Macros/Sources/ObservationMacros/CMakeLists.txt

@@ -51,7 +51,10 @@ add_custom_command_target(
     COMMAND "${CMAKE_COMMAND}" -E rm -f "${module_file}"
     OUTPUT ${module_base}
     COMMENT "Generating module directory for ${module_name}")
-add_dependencies(${library_name} ${create_module_dirs_dependency_target})
+add_dependencies(${library_name} 
+  ${create_module_dirs_dependency_target} 
+  libSwiftScan # Placeholder that gets SwiftSyntax et-al built
+)
 
 # Build the module with library evolution enabled and install into the
 # appropriate locations.
@@ -62,12 +65,13 @@ target_compile_options("${library_name}" PRIVATE
     -emit-module-interface-path;
     "${module_interface_file}" ;
     -I ${CMAKE_BINARY_DIR}/lib/${SWIFT_HOST_LIBRARIES_SUBDIRECTORY};
+    -Xlinker -L${CMAKE_BINARY_DIR}/lib/${SWIFT_HOST_LIBRARIES_SUBDIRECTORY};
     -target;${target}>)
 
 target_link_libraries(${library_name}
     PRIVATE
-    SwiftSyntax::SwiftSyntax
-    SwiftSyntax::SwiftSyntaxMacros
+    SwiftSyntax
+    SwiftSyntaxMacros
 )
 
 swift_install_in_component(TARGETS "${library_name}"