zlib autoconf question

[Lars Magne Ingebrigtsen]

I'm not sure whether it's really necessary to check for zlib -- does
Emacs even build without png support these days? -- but perhaps it is.

Anyway, I wrote the obvious:

  AC_CHECK_LIB(z, inflateInit2, HAVE_ZLIB=yes, HAVE_ZLIB=no)

And that fails with:

/home/larsi/src/emacs/trunk/conftest.c:118: undefined reference to 
`inflateInit2'

But inflateInit2 definitely exists (it's the function decompress.c
uses).

However, running strings over libz says:

inflateReset
inflateReset2
inflateInit2_
inflateInit_

And

  AC_CHECK_LIB(z, inflateInit2_, HAVE_ZLIB=yes, HAVE_ZLIB=no)

works!

What's up with that?

-- 
(domestic pets only, the antidote for overdose, milk.)
  No Gnus T-Shirt for sale: http://ingebrigtsen.no/no.php
  and http://lars.ingebrigtsen.no/2013/08/twenty-years-of-september.html