[multiple changes]

2011-08-02  Ed Schonberg  <schonberg@adacore.com>

	* sem_prag.adb (Chain_PPC): Implement AI04-0230: null procedures can
	only have inheritable classwide pre/postconditions.

2011-08-02  Javier Miranda  <miranda@adacore.com>

	* a-tags.ads, a-tags.adb (Check_TSD): New subprogram.
	* rtsfind.ads (RE_Check_TSD): New runtime entity.
	* exp_disp.adb (Make_DT): Generate call to the new runtime routine that
	checks if the external tag of a type is the same as the external tag
	of some other declaration.

From-SVN: r177159