Diagnostics that should not be translated

[Roland Illig <roland.illig@gmx.de>]

Hi,

the gcc.pot file currently contains more than 12000 messages to be
translated, which is a very high number. Many of these messages are
diagnostics, and they can be categorized as follows:

* errors in user programs, reported via error ()
* additional info for internal errors, reported via error ()
* internal errors, reported via gfc_internal_error ()
* others

In my opinion, there is no point in having internal error messages
translated, since their only purpose is to be sent back to the GCC
developers, instead of being interpreted and acted upon by the GCC user.
By not translating the internal errors, the necessary work for
translators can be cut down by several hundred messages.

Therefore the internal errors should not be translated at all.
https://gcc.gnu.org/codingconventions.html#Diagnostics currently
mentions a few ways of emitting diagnostics, but there is no way to
produce untranslated diagnostics. Therefore I'd like to have a new
function error_no_i18n that is used instead of error for nonfatal
internal errors, like this:

@code{error_no_i18n} is for diagnostics that are printed before invoking
internal_error. They are not translated.

(I don't care about the exact function name, though. :))

Regards,
Roland