This patch corrects a problem in the compiler whereby the determination of
scope levels during the generation of accessibility checks for function calls
within range constraints leads to a compiler crash due to the type not being
fully analyzed at the point in which its scope depth must be obtained.

Tested on x86_64-pc-linux-gnu, committed on trunk

gcc/ada/

	* sem_util.adb
	(Innermost_Master_Scope_Depth): Detect and handle case where scope
	depth is not set on an enclosing scope.