Merge pull request swiftlang#27888 from drodriguez/cmake-dontóverwirte-job-pools

[cmake] Do not override existing JOB_POOLS.

Author: compnerd

CMakeLists.txt

@@ -20,7 +20,7 @@ else()
   # Make a job pool for things that can't yet be distributed
   cmake_host_system_information(
     RESULT localhost_logical_cores QUERY NUMBER_OF_LOGICAL_CORES)
-  set_property(GLOBAL PROPERTY JOB_POOLS local_jobs=${localhost_logical_cores})
+  set_property(GLOBAL APPEND PROPERTY JOB_POOLS local_jobs=${localhost_logical_cores})
   # Put linking in that category
   set(CMAKE_JOB_POOL_LINK local_jobs)
 endif()