[yocto] why do numerous .bb files set "PARALLEL_MAKE"?

[Robert P. J. Day]

  stumbled over this so i did a more thorough search:

$ grep -w PARALLEL_MAKE $(find . -name *.bb)
./meta/recipes-qt/qt-apps/qmmp_0.5.1.bb:PARALLEL_MAKE = ""
./meta/recipes-core/eggdbus/eggdbus_0.6.bb:PARALLEL_MAKE = ""
./meta/recipes-core/gettext/gettext_0.16.1.bb:PARALLEL_MAKE = ""
./meta/recipes-core/gettext/gettext_0.18.1.1.bb:#PARALLEL_MAKE = ""
./meta/recipes-bsp/pciutils/pciutils_3.1.7.bb:PARALLEL_MAKE = ""
./meta/recipes-extended/sat-solver/sat-solver_git.bb:PARALLEL_MAKE=""
./meta/recipes-extended/bash/bash_3.2.48.bb:PARALLEL_MAKE = ""
./meta/recipes-extended/tcp-wrappers/tcp-wrappers_7.6.bb:PARALLEL_MAKE = ""
./meta/recipes-extended/groff/groff_1.20.1.bb:PARALLEL_MAKE = ""
... more snipped ...

  why are individual recipes setting PARALLEL_MAKE to the empty
string?  it's a *build* option, why would it have any relevance to
individual .bb files?

  conversely, i don't see a single .bb file that sets
BB_NUMBER_THREADS.  the above just looks ... odd.

rday

-- 

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Robert P. J. Day                                 Ottawa, Ontario, CANADA
                        http://crashcourse.ca

Twitter:                                       http://twitter.com/rpjday
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