styleg-c.ads, [...] (Missing_Overriding): new procedure to implement style check...

styleg-c.ads, [...] (Missing_Overriding): new procedure to implement style check that overriding operations are...

2008-08-20  Ed Schonberg  <schonberg@adacore.com>

	* styleg-c.ads, styleg-c.adb (Missing_Overriding): new procedure to
	implement style check that overriding operations are explicitly marked
	at such.

	* style.ads (Missing_Overriding): new procedure that provides interface
	to previous one.

	* stylesw.ads, stylesw.adb: New style switch -gnatyO, to enable check
	that the declaration or body of overriding operations carries an
	explicit overriding indicator.

	* sem_ch8.adb
	(Analyze_Subprogram_Renaming): if operation is overriding, check whether
	explicit indicator should be present.

	* sem_ch6.adb (Verify_Overriding_Indicator,
	Check_Overriding_Indicator): If operation is overriding, check whether
	declaration and/or body of subprogram should be present

From-SVN: r139316