Add dependency on the libdispatch-install step

Libraries in sourcekitd depending on the external libdispatch project
appear to only depend on the *build* step, but really need the install
to happen as well since we are linking to the installed location.

Author: benlangmuir

tools/SourceKit/CMakeLists.txt

@@ -134,6 +134,8 @@ if(NOT "${CMAKE_SYSTEM_NAME}" STREQUAL "Darwin")
                           # ensure that we strip out the DESTDIR environment
                           # from the sub-build
                           ${CMAKE_COMMAND} -E env --unset=DESTDIR ${CMAKE_COMMAND} --build . --target install
+                        STEP_TARGETS
+                          install
                         BUILD_BYPRODUCTS
                           <INSTALL_DIR>/lib/${CMAKE_SHARED_LIBRARY_PREFIX}dispatch${CMAKE_SHARED_LIBRARY_SUFFIX}
                           <INSTALL_DIR>/lib/${CMAKE_IMPORT_LIBRARY_PREFIX}dispatch${CMAKE_IMPORT_LIBRARY_SUFFIX}
@@ -169,6 +171,9 @@ if(NOT "${CMAKE_SYSTEM_NAME}" STREQUAL "Darwin")
                             INTERFACE_INCLUDE_DIRECTORIES
                               ${SWIFT_PATH_TO_LIBDISPATCH_SOURCE}/src/BlocksRuntime)
 
+    add_dependencies(dispatch libdispatch-install)
+    add_dependencies(BlocksRuntime libdispatch-install)
+
     swift_install_in_component(sourcekit-inproc
                                FILES
                                  $<TARGET_FILE:dispatch>