Just for your information, if it can help :
I have no problem when I build exchndl.dll as a separate build.
I have in my mingw32\lib folder a libintl.dll.a. It's obviously this one which is linked, because if I rename it, the build of exchndl.dll fails. Apparently, when I look inside this file with a binary editor, I can see a reference to libintl-8.dll. So this is probably the reason why I have no problem when builing exchndl.dll. But, I can't remember from where it comes, and it's a rather old file (19 Sept 2007 !). I have also with the same date a libintl.a and a libintl.la in this lib folder, but renaming them does not change anything, so I believe they are not used in my case.
In the mingw32\bin folder I have effectively a libintl-8.dll but no libintl.dll.
gd_on