patch 9.1.0459: Vim9: import autoload does not work with symlink

Problem:  Vim9: import autoload does not work with symlink
          (Olivier Dormond)
Solution: set sn_autoload_prefix in check_script_symlink
          (nwounkn)

fixes: #14775
closes: #14885

Signed-off-by: nwounkn <nwounkn@gmail.com>
Signed-off-by: Christian Brabandt <cb@256bit.org>

src/scriptfile.c

@@ -435,8 +435,13 @@ check_script_symlink(int sid)
 	    si = SCRIPT_ITEM(sid);
 	    si->sn_sourced_sid = real_sid;
 	    if (new_sid)
+	    {
 		SCRIPT_ITEM(real_sid)->sn_import_autoload
 						    = si->sn_import_autoload;
+		if (si->sn_autoload_prefix != NULL)
+			SCRIPT_ITEM(real_sid)->sn_autoload_prefix =
+				vim_strsave(si->sn_autoload_prefix);
+	    }
 	}
     }
     vim_free(real_fname);

src/testdir/test_vim9_import.vim

@@ -3068,7 +3068,10 @@ def Test_vim9_import_symlink()
     var lines =<< trim END
         vim9script
         import autoload 'bar.vim'
-        g:resultFunc = bar.Func()
+        def FooFunc(): string
+          return bar.Func()
+        enddef
+        g:resultFunc = FooFunc()
         g:resultValue = bar.value
     END
     writefile(lines, 'Xto/plugin/foo.vim')

src/version.c

@@ -704,6 +704,8 @@ static char *(features[]) =
 
 static int included_patches[] =
 {   /* Add new patch number below this line */
+/**/
+    459,
 /**/
     458,
 /**/