- engine: liboakengine.dylib intentionally leaves olive::k_app_version
to the final executable (olive-version-obj); whitelist that symbol
with -U on Apple, where undefined symbols in dylibs are an error
(ELF allows them by default).
- app/common/configwrapper.h: only declare the int64_t/uint64_t
conversion/assignment overloads on Linux LP64, where they differ
from qint64/quint64; elsewhere both are long long and the extra
overloads are redeclarations.