Carp 1.25 made a change to its formatting, adding a period at the end of the
message. This can mess up tests and code that are looking for error messages.
Carp::Fix::1_25 makes the message consistent, regardless of what version of
Carp you're using.

Carp::Fix::1_25 exports its own carp functions, which change the Carp message
to match the 1.25 version. Carp::Fix::1_25 otherwise acts exactly like Carp and
it will honor Carp global variables such as @CARP_NOT and %%Carp::Internal.

Why do this instead of just upgrading Carp? Upgrading Carp would affect all
installed code all at once. You might not be ready for that, or you might not
want your module to foist that on its users. This lets you fix things one
namespace at a time.