The `ghc_unique_counter64` symbol was introduced in the RTS in the 64-bit unique refactor (!10568) which has been backported to %9.6.7 and %9.8.4. Update the CPP to reflect this. Fixes #25576.
mentioned in merge request !13743 (closed)
mentioned in commit a7402f41
mentioned in merge request !13913 (merged)
mentioned in issue #25963
mentioned in commit 0dabd3c1
mentioned in merge request !14238