m4 is broken -- can't rename builtins (patch in PR)

[Craig Boston]

Hi -hackers:

Just wondering if I could get a committer's attention to look at
bin/59883.  It seems that m4 has been broken for quite some time -- at
least in the ability to rename builtin macros -- defn() doesn't work
correctly anymore.  I've been using the simple patch in the PR locally
for the last several months and have yet to run into any problems with
it.  I guess not many people use the bundled m4 for anything much more
complicated than making sendmail.cf files ;)

I'm not sure who is the active maintainer for m4 is, or even if there is
one.  CC: tjr & smkelly as they are the last couple people to touch the
code in a while.  I hope I'm sending this to the right place :)

Thanks!
Craig