BUG/MINOR: makefile: use USE_LIBATOMIC instead of USE_ATOMIC

The issue was introduced with commit c108f37c2 ("BUILD: makefile:
rework 51D to split v3/v4"), and is also related to commit b16d9b58
("BUILD: makefile: never force -latomic, set USE_LIBATOMIC instead")
where USE_ATOMIC has been replaced.
1 file changed