[Ada] Better exception message on Invalid_Switch exception

Improve the error message introduced in the recent commit for
Invalid_Switch exception.

2019-08-13  Dmitriy Anisimkov  <anisimko@adacore.com>

gcc/ada/

	* libgnat/g-comlin.adb (Getopt): Quote unrecognized switch in
	Invalid_Switch exception message.

From-SVN: r274333

gcc/ada/ChangeLog

+2019-08-13  Dmitriy Anisimkov  <anisimko@adacore.com>
+
+	* libgnat/g-comlin.adb (Getopt): Quote unrecognized switch in
+	Invalid_Switch exception message.
+
 2019-08-13  Yannick Moy  <moy@adacore.com>
 
 	* sem_util.adb (Traverse_More_Func): Take into account

gcc/ada/libgnat/g-comlin.adb

@@ -754,7 +754,7 @@ package body GNAT.Command_Line is
             Parser.Current_Index := End_Index + 1;
 
             raise Invalid_Switch with
-              "Unrecognized option " & Full_Switch (Parser);
+              "Unrecognized option '" & Full_Switch (Parser) & ''';
          end if;
 
          End_Index := Parser.Current_Index + Max_Length - 1;
@@ -885,7 +885,7 @@ package body GNAT.Command_Line is
                      Extra   => Parser.Switch_Character);
                   Parser.Current_Index := Arg'Last + 1;
                   raise Invalid_Switch with
-                    "Unrecognized option " & Full_Switch (Parser);
+                    "Unrecognized option '" & Full_Switch (Parser) & ''';
                end if;
          end case;