Errors and questions on clutter gtk with mingw-w64

[Eugen Dedu <Eugen Dedu pu-pm univ-fcomte fr>]

Hi all,

I have a very strange error when building clutter gtk with mingw-w64:

  CCLD     libclutter-gtk-1.0.la
libtool: link: warning: undefined symbols not allowed in i686-pc-mingw32 
shared libraries

and no .dll is generated.

If I add "-no-undefined" to linker, no error is shown and the dll is 
generated.

I have several questions:

1. Why do I have this error?  Is this a bug in clutter gtk?

(2. By the way, I had to do that to fix a compile error:
sed -i -e 
's#<clutter/clutter-win32.h>#<clutter/win32/clutter-win32.h>#g' 
$(CLUTTERGTK_DIR)/clutter-gtk/gtk-clutter-actor.c)

3. Why with -no-undefined the dll *is* generated and nothing is 
reported?  As I read from Internet and ld man page:
--no-undefined
-z defs
    Report unresolved symbol references from regular object files. This 
is done even if the linker is creating a non-symbolic shared library. 
The switch --[no-]allow-shlib-undefined controls the behaviour for 
reporting unresolved references found in shared libraries being linked in.
So that flag should have reported the unresolved symbols and not fix 
anything!

4. Why the flag is -no... and not --no...?  I do not see anywhere 
-no..., but only --no...  If I use --no... I still have the link error, 
as if the flag were not taken into account.

Best regards,
--
Eugen