cp_error calls not picked up by exgettext

[Joseph S. Myers]

Hundreds of error messages in calls to cp_error, cp_warning and cp_pedwarn
are not picked up by exgettext, maybe because these are defined as
object-like macros for error, warning and pedwarn in cp-tree.h.  We
clearly ought to fix this before shipping a new post-feature-freeze .pot 
to the translation project.  What would the appropriate fix be?

* Globally replace these names, being considered obsolete, with the values 
they are defined to?

* Make some way for gettext or exgettext to pick them up?

-- 
Joseph S. Myers
jsm28@cam.ac.uk