now print error if chdir fails

sudo_realpath.c

@@ -208,7 +208,11 @@ static void realpath_restore(cwd)
 
     /* relinquish root privs and chdir to where we started... */
     be_user();
-    (void) chdir(cwd);
+    if (chdir(cwd)) {
+	fprintf(stderr, "Error: cannot change dir back to %s, sudo aborting!\n",
+			cwd);
+	exit(1);
+    }
 
     errno = old_errno;
 }