made the pack completely portable and wrote relevent bat files to go with it

gitportable/usr/share/vim/vim91/compiler/xmllint.vim

@@ -0,0 +1,24 @@
+" Vim compiler file
+" Compiler:	Libxml2 Command-Line Tool
+" Maintainer:	Doug Kearns <dougkearns@gmail.com>
+" Last Change:	2024 Apr 03
+
+if exists("current_compiler")
+  finish
+endif
+let current_compiler = "xmllint"
+
+let s:cpo_save = &cpo
+set cpo&vim
+
+CompilerSet makeprg=xmllint\ --valid\ --noout
+CompilerSet errorformat=%E%f:%l:\ %.%#\ error\ :\ %m,
+		       \%W%f:%l:\ %.%#\ warning\ :\ %m,
+		       \%-Z%p^,
+		       \%C%.%#,
+		       \%terror:\ %m,
+		       \%tarning:\ %m,
+		       \%-G%.%#
+
+let &cpo = s:cpo_save
+unlet s:cpo_save