partly fixed... / #3810

Sorry for being too restrictive. I don't want to look like a "boss"...

Using %d fixed the missing day problem. It took a while until I figured out, how to get a German date be localized. Since the %d does the fix, let us keep the current implementation.
If some users complain, we can easily revert the changes.

I don't think that implementing an own localized version of gm would be a good idea. Although it would be easy, it would further slow down rendering.

Could you add a small chapter on to be translated locale settings to the Translation Guide. I see that there are four important keys:

 en_US.utf8,en_US,enu|list of locales
 %b %d, %Y|strftime format string
 %I:%M%P|strftime format string
 %a %b %d, %Y %I:%M%P|strftime format string

or are there some more? Maybe some links to the php functions will help translators to figure out what is meant...