Linking clause deleted from GNAT GPL

[null@iang.info]

Hello,

Maybe this subject was discussed before, but I'd like some
clarification. The GNU Ada compiler (GNAT) from FSF is distributed
under GPL with this special linking exception:

"As a special exception, if other files instantiate generics from this
unit, or you link this unit with other files to produce an executable,
this unit does not by itself cause the resulting executable to be
covered by the GNU General Public License. This exception does not
however invalidate any other reasons why the executable file might be
covered by the GNU Public License."

But in the latest GNAT version distributed by AdaCore, this clause was
deleted in all library source files, therefore forcing all executables
to be covered by GPL. The question is: did AdaCore have the right to
remove this clause? Since FSF owns the copyright of GCC, this is not
obvious to me.

Thanks!

-- 
Patrick