3c'>make update_pch also consider files in <module>/src/**/inc

Age	Commit message (Expand)	Author
Luboš Luňák
2019-12-01	Introduce o3tl::optional as an alias for std::optional	Stephan Bergmann
2019-10-18	make bin/update_pch.s always include code in trivial #if's	Luboš Luňák
2019-05-09	regenerate PCH headers for the 4 new levels	Luboš Luňák
2017-09-22	Fresh run of bin/update_pch.sh	Mike Kaganski