With %cargo_prep becoming parameterized in v25, Fedora and RHEL macros became incompatible to the point that a RHEL-ified spec file, even conditionally, cannot be parsed on Fedora. This should limit the error to actual unconditional use of the flag during a Fedora build (which should never happen) until such time that the Fedora and RHEL macros are in sync.
With %cargo_prep becoming parameterized in v25, Fedora and RHEL macros became incompatible to the point that a RHEL-ified spec file, even conditionally, cannot be parsed on Fedora. This should limit the error to actual unconditional use of the flag during a Fedora build (which should never happen) until such time that the Fedora and RHEL macros are in sync.