posix: define M_PI and other stuff in Zephyr sketches #739

Job	Run time
Build and package cores	9m 33s
Split off zephyr	17s
Split off zephyr_unoq	6s
Split off zephyr_main	13s
Split off zephyr_contrib	17s
Test zephyr_main:portentac33	2m 36s
Test zephyr_main:portentah7	2m 32s
Test zephyr_main:opta	2m 37s
Test zephyr_main:niclasense	2m 27s
Test zephyr:unoq	2m 24s
Test zephyr_main:nano33ble	2m 36s
Test zephyr_contrib:frdm_mcxn947	2m 26s
Test zephyr_main:giga	2m 35s
Test zephyr_contrib:ek_ra8d1	2m 25s
Test zephyr_contrib:frdm_rw612	2m 28s
Collect logs	7s
Publish jsons	13s
Publish core	0s
verify-core	0s
cleanup-artifacts	3s
	35m 55s

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