exp_ch3.adb (Predef_Spec_Or_Body): When the type is abstract, only create an abstract subprogram in the case of 'Input.

2007-09-10  Gary Dismukes  <dismukes@adacore.com>
	    Thomas Quinot  <quinot@adacore.com>

	* exp_ch3.adb (Predef_Spec_Or_Body): When the type is abstract, only
	create an abstract subprogram in the case of 'Input. For 'Output we now
	create a real spec/body when the type is abstract, since it can
	potentially be called.
	(Predefined_Primitive_Bodies): Now allow the creation of a predefined
	body for 'Output when the type is abstract (only the creation of the
	body for 'Input is excluded when the type is abstract).
	(Stream_Operation_OK): Add an additional condition in the return
	statement, so that False will be returned for TTS_Stream_Input if the
	associated tagged type is an abstract extension. Add comments for
	return statement.
	(Expand_N_Object_Declaration): For the case of a shared passive
	variable, insert init proc call only after the shared variable
	procedures have been processed, because the IP call needs to undergo
	shared passive variable reference expansion, which requires these
	procedures to be available (and elaborated).

From-SVN: r128335