Implement exceptions specifiers for implicit member functions.

Implement exceptions specifiers for implicit member functions.

cp:
	Implement exceptions specifiers for implicit member functions.
	* cp-tree.h (merge_exceptions_specifiers): Declare new function.
	* method.c (synthesize_exception_spec): New function.
	(locate_dtor, locate_ctor, locate_copy): New functions.
	(implicitly_declare_fn): Generate the exception spec too.
	* search.c (check_final_overrider): Check artificial functions
	too.
	* typeck2.c (merge_exception_specifiers): New function.
testsuite:
	* g++.old-deja/g++.eh/spec6.C: Remove remaining XFAIL.

From-SVN: r38659