catkin build -v -p 4 --jobserver-limit 3 -i

echo  --jobserver-fds=5,6 -j | grep -- '--jobserver-fds'
--jobserver-fds=5,6 -j
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CMAKE_PREFIX_PATH:           /private/tmp/test-workspace/devel:/tmp/test-workspace/devel
Workspace:                   /private/tmp/test-workspace
Buildspace:                  /private/tmp/test-workspace/build
Develspace:                  /private/tmp/test-workspace/devel
Installspace:                /private/tmp/test-workspace/install
DESTDIR:                     None
----------------------------------------------------------------------------------------
Isolate Develspaces:         False
Install Packages:            False
Isolate Installs:            False
----------------------------------------------------------------------------------------
Additional CMake Args:       None
Additional Make Args:        None
Additional catkin Make Args: None
----------------------------------------------------------------------------------------
WARNING: Package name "foo-1" does not follow the naming conventions. It should start with a lower case letter and only contain lower case letters, digits and underscores.
WARNING: Package name "foo-2" does not follow the naming conventions. It should start with a lower case letter and only contain lower case letters, digits and underscores.
WARNING: Package name "foo-3" does not follow the naming conventions. It should start with a lower case letter and only contain lower case letters, digits and underscores.
WARNING: Package name "foo-4" does not follow the naming conventions. It should start with a lower case letter and only contain lower case letters, digits and underscores.
Found '4' packages in 0.0 seconds.
Starting ==> foo-1
[foo-1] ==> '/private/tmp/test-workspace/build/foo-1/build_env.sh /usr/bin/make cmake_check_build_system' in '/private/tmp/test-workspace/build/foo-1'
Starting ==> foo-2
[foo-2] ==> '/private/tmp/test-workspace/build/foo-2/build_env.sh /usr/bin/make cmake_check_build_system' in '/private/tmp/test-workspace/build/foo-2'
Starting ==> foo-3
[foo-3] ==> '/private/tmp/test-workspace/build/foo-3/build_env.sh /usr/bin/make cmake_check_build_system' in '/private/tmp/test-workspace/build/foo-3'
Starting ==> foo-4
[foo-3] <== '/private/tmp/test-workspace/build/foo-3/build_env.sh /usr/bin/make cmake_check_build_system' finished with return code '0'
[foo-3] ==> '/private/tmp/test-workspace/build/foo-3/build_env.sh /usr/bin/make --jobserver-fds=3,4 -j' in '/private/tmp/test-workspace/build/foo-3'
[foo-2] <== '/private/tmp/test-workspace/build/foo-2/build_env.sh /usr/bin/make cmake_check_build_system' finished with return code '0'
[foo-2] ==> '/private/tmp/test-workspace/build/foo-2/build_env.sh /usr/bin/make --jobserver-fds=3,4 -j' in '/private/tmp/test-workspace/build/foo-2'
[foo-1] <== '/private/tmp/test-workspace/build/foo-1/build_env.sh /usr/bin/make cmake_check_build_system' finished with return code '0'
[foo-1] ==> '/private/tmp/test-workspace/build/foo-1/build_env.sh /usr/bin/make --jobserver-fds=3,4 -j' in '/private/tmp/test-workspace/build/foo-1'
[foo-1] foo1
[foo-3] foo1
[foo-2] foo1
[foo-1] Built target foo1
[foo-2] Built target foo1
[foo-3] Built target foo1
[foo-1] foo2
[foo-2] foo2
[foo-3] foo2
[foo-1] Built target foo2
[foo-3] Built target foo2
[foo-2] Built target foo2
[foo-1] foo3
[foo-3] foo3
[foo-2] foo3
[foo-1] Built target foo3
[foo-3] Built target foo3
[foo-2] Built target foo3
[foo-3] foo4
[foo-1] foo4
[foo-2] foo4
[foo-3] Built target foo4
[foo-1] Built target foo4
[foo-2] Built target foo4
[foo-2] <== '/private/tmp/test-workspace/build/foo-2/build_env.sh /usr/bin/make --jobserver-fds=3,4 -j' finished with return code '0'