CC from environment is used to initialize CMAKE_C_COMPILER so
setting CMAKE_C_COMPILER explicitly isn't needed.
The syntax in ci_build.bash was broken in case one wished to put
spaces in CC.
(cherry picked from commit 0c1e6d900bac127464fb30a854776e1810ab5f16)
hw.ncpu counts all CPUs including inactive ones. hw.activecpu counts
only the active CPUs.
(cherry picked from commit 97f0ee0f1f903f4e7c4ea23e9b89d687025d2992)
We discussed the name and it's less cognitive load to just call it '.bash'
so you don't have an immediate question about if bashisms are OK.
(cherry picked from commit 73f629e321b74f68c9954728fa4f19261afccf46)
