[This issue concerns redhat-rpm-config as well.]

Every now and then, there's a need to build packages that mangle the
resulting binary package name from a single unchanged source package,
based on some build time conditions.

Let's assume package (SRPM) foo.  Based on some options, the binary
rpm built from it can result in foo-bar or foo-quux being output.  But
the debuginfo package will always be named foo-debuginfo, making it
impossible to store the debuginfo packages resulting from foo-bar and
foo-quux in the same directory/repository/whatever (since they're
always the same, foo-debuginfo instead of foo-bar-debuginfo and
foo-quux-debuginfo).

Making the name of the debuginfo package customizable would help, for
example by defining this in foo.spec:

  %define debuginfo_name %{name}-bar-debuginfo

...could result in the debuginfo package "foo-bar-debuginfo".