Feature configuration: add a field required_variables on flag_sets.
This allows to prevent expansion of flag sets based on whether build variables
are available. If required_variables is not set, and a variable that is
referenced in the flag_set's flags is not available, the build will fail.
We need the new behavior when some input files (for example profile data in
FDO enabled builds) are only available for a subset of the translation units of
a given target.
RELNOTES: None.
PiperOrigin-RevId: 100028996
1 file changed
