freeze.adb: Make Freeze_Fixed_Point_Type visible, for use in sem_attr.

freeze.adb: Make Freeze_Fixed_Point_Type visible, for use in sem_attr.

	* freeze.adb: Make Freeze_Fixed_Point_Type visible, for use in
	sem_attr.

	* sem_attr.adb: Simplify previous fix for Address.
	(Set_Bounds): If prefix is a non-frozen fixed-point type, freeze now,
	to avoid anomalies where the bound of the type appears to raise
	constraint error.

	* lib-xref.adb (Output_Refs): Make sure pointers are always properly
	handled.

	* sem_ch12.adb (Analyze_Subprogram_Instantiation): Check for a
	renamed unit before checking for recursive instantiations.

	* prj.ads: Add comments for some of the fields.

From-SVN: r47902