gettext .mo files and nullentry

[Joachim Metz]

Dear gettext team,

First of all great work on gettext.

I'm currently looking into .mo files and was missing information about
the nullentry in the documentation.
Mainly the required and optional entries, e.g. 'Content-Type:' with a
'charset=' seems required.
Could you update the documentation.

Looking at the libintl-0.14.4 code I found that libintl has a logical
error (the same error consists in glibc 2.9).
libintl searches for the 'charset=', 'nplural=' and 'plural='
sub-string in the nullentry, but it fails to check if the definition
(line) they are in are the right one, e.g. if they start with
'Content-Type:' or 'Plural-Forms:'.

Kind regards,
Joachim Metz