can_unit_do_activity_targeted_at(): ACTIVITY_PILLAGE case may fall through
It's the ACTIVITY_PILLAGE case above that is falling through *to* ACTIVITY_EXPLORE.
The problem is in macro RETURN_IS_ACTIVITY_ENABLED_UNIT_ON() that has no return for invalid value.
With -Wimplicit-fallthrough in master:
../../../src/common/unit.c: In function ‘can_unit_do_activity_targeted_at’:
../../../src/common/unit.c:913:5: error: this statement may fall through -Werror=implicit-fallthrough=
~../../../src/common/unit.c:913:5: note: in definition of macro ‘RETURN_IS_ACTIVITY_ENABLED_UNIT_ON’
~../../../src/common/unit.c:1019:3: note: here
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