ncmpcpp failed to build in Fedora Rawhide (the Fedora development version which will be Fedora 43/44 in future) because the bash has been updated there from 5.2 to 5.3 and a significant behavior with the boost library has changed. For more details you may look into the RedHat bug below. Also some additional links are there explaining the issue: https://bugzilla.redhat.com/show_bug.cgi?id=2385207

I'm opening this issue because I think the patch we added to fix this could be interesting for you https://src.fedoraproject.org/rpms/ncmpcpp/pull-request/1#request_diff