sem_ch3.adb (Analyze_Variant_Part): check that type of discriminant is discrete before analyzing choices.

	* sem_ch3.adb (Analyze_Variant_Part): check that type of discriminant
	is discrete before analyzing choices.

	* bindgen.adb (Gen_Output_File_Ada): Generate a new C-like string
	containing the name of the Ada Main Program. This string is mainly
	intended for the debugger.
	(Gen_Output_File_C): Do the equivalent change when generating a C file.

	* ali.adb: Set new Dummy_Entry field in dependency entry

	* ali.ads: Add Dummy_Entry field to source dependency table

	* bcheck.adb (Check_Consistency): Ignore dummy D lines

	* lib-writ.adb (Writ_ALI): Write dummy D lines for missing source files

	* lib-writ.ads: Document dummy D lines for missing files.

	* types.ads: (Dummy_Time_Stamp): New value for non-existant files

From-SVN: r48126