[Ada] System.Os_Lib.Normalize_Pathname: fix incorrect comment

2018-10-09  Vasiliy Fofanov  <fofanov@adacore.com>

gcc/ada/

	* libgnat/s-os_lib.ads (Normalize_Pathname): Fix incorrect
	comment.

From-SVN: r264963

gcc/ada/ChangeLog

+2018-10-09  Vasiliy Fofanov  <fofanov@adacore.com>
+
+	* libgnat/s-os_lib.ads (Normalize_Pathname): Fix incorrect
+	comment.
+
 2018-10-09  Arnaud Charlet  <charlet@adacore.com>
 
 	* vxlink.adb: Remove pragma Annotate, no longer needed.

gcc/ada/libgnat/s-os_lib.ads

@@ -545,8 +545,8 @@ package System.OS_Lib is
    --  directory pointed to. This is slightly less efficient, since it
    --  requires system calls.
    --
-   --  If Name cannot be resolved, is invalid (for example if it is too big) or
-   --  is null on entry (for example if there is symbolic link circularity,
+   --  If Name is empty or the path contains symbolic links that can't be
+   --  resolved (for example there is a symbolic link circularity,
    --  e.g. A is a symbolic link for B, and B is a symbolic link for A), then
    --  Normalize_Pathname returns an empty string.
    --