Internationalization through GNU gettext

[Bruno Haible]

GNU gettext version 0.25 and newer supports the D language.

This was announced in 
https://lists.gnu.org/archive/html/info-gnu/2025-05/msg00000.html.

In detail:
   - It ships with a library libintl_d.a, that contains the 
runtime code for using GNU gettext message catalogs in the D 
programming language.
   - The 'xgettext' program supports extracting localizable 
messages from D code into a POT file.
   - When doing so, 'xgettext' adds 'd-format' markers for D 
format strings.
   - The msgfmt program, when invoked as 'msgfmt -c', verifies the 
syntax of translations of D format strings.
   - A new example 'hello-d' has been added, that can be used as a 
starting point for internationalized packages.

This support of the D language follows all the good usage 
patterns from the other programming languages.