vim syntax highlighting for embedded pod in XS

[muppet <scott asofyet org>]

the XS "language" allows you to embed POD directly in the XS file, at 
any point.  xsubpp strips the POD from the first directive found in an 
open area up to a =cut, and replaces all such stripped sections with a 
C comment that says "/* stripped embedded pod */".

because of that replacement, you can't put the pod in a C comment, and 
thus you have a bunch of bare text in your XS file that messes with 
vim's syntax highlighting.

for those of you who like to hack XS and use vim 6 to do it, i have 
found something that fixes it:

i created a new file, .vim/after/syntax/xs.vim ... this file will be 
run by vim after all the normal syntax highlighting stuff, and thus is 
to be used for overrides and additions.  into that, i copied a relevant 
section from the perl.vim syntax file 
/usr/share/vim/vim61/syntax/perl.xs.  i'm no vim syntax wizard, so i 
wasn't sure how to make the syn include line look for pod.vim in the 
path correctly (the code that's there appears to look for one in the 
same directory as the file currently being executed), so i hardcoded 
the path.  naturally, you'll have to find the right path for your 
system (or do it correctly :-).

~/.vim/after/syntax/xs.vim:
-=-=-=-=-=-=-
" POD starts with ^=<word> and ends with ^=cut

if exists("perl_include_pod")
  " Include a while extra syntax file
"  syn include @Pod <sfile>:p:h/pod.vim
  syn include @Pod /usr/share/vim/vim61/syntax/pod.vim
  unlet b:current_syntax
  if exists("perl_fold")
    syn region perlPOD start="^=[a-z]" end="^=cut" 
contains= Pod,perlTodo keepend fold
  else
    syn region perlPOD start="^=[a-z]" end="^=cut" 
contains= Pod,perlTodo keepend
  endif
else
  " Use only the bare minimum of rules
  if exists("perl_fold")
    syn region perlPOD start="^=[a-z]" end="^=cut" fold
  else
    syn region perlPOD start="^=[a-z]" end="^=cut"
  endif
endif
-=-=-=-=-=-=-


annoyingly enough, i couldn't figure out how to get it to actually turn 
on the full pod syntax rules, either for my xs file or normal perl 
files -- it just treats the pod section like comments.

anyway, hope that's helpful.  if anybody knows what i did wrong, or 
wants to illustrate how emacs is so much simpler and i should be using 
that instead[1], feel free.