runtime(dist): add legacy version for central vim library

Also, enable the zip and gzip plugins by default, unless those variables
were not explicitly set by the user.

related: #13413

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

runtime/autoload/dist/vim9.vim

@@ -0,0 +1,17 @@
+vim9script
+
+# Vim runtime support library
+#
+# Maintainer:	The Vim Project <https://github.com/vim/vim>
+# Last Change:	2023 Oct 25
+
+export def IsSafeExecutable(filetype: string, executable: string): bool
+    var cwd = getcwd()
+    return get(g:, filetype .. '_exec', get(g:, 'plugin_exec', 0))
+      && (fnamemodify(exepath(executable), ':p:h') !=# cwd
+          || (split($PATH, has('win32') ? ';' : ':')->index(cwd) != -1
+              && cwd != '.'))
+enddef
+
+# Uncomment this line to check for compilation errors early
+# defcompile