[gtkada] lgthread problem

[Sami EVANGELISTA]

hi everybody

i have tried to use the Gdk.Threads package for a multi-threaded 
application. But when i compile with the -lgthread option as in :

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gnatmake -gnatf -I/usr/lib/ada/adainclude checker.adb -largs -lgtkada 
-lgthread
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it gives me the following error message :

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ld: ne peut trouver -lgthread
gnatmake: *** link failed.
------------------------------------------------------------------------------------------

my versions are :
gnat 1.13
gtk 1.2
gtkada 1.2.12

i have tried to reinstall gtk and gtkada but the problem persist.
i have also found the libgthread-2.0.so.0.0.6 in my /usr/lib directory
does anybody have an idea of the problem?

thanks for any response

Sami Evangelista