# zlib stuff basically copied from TeXLive

  EXTRA_ZLIB_INCLUDE=
  EXTRA_ZLIB_LIBDIR=

  if test "$with_system_zlib" = yes; then
    if test "x$with_zlib_libdir" != x; then
      EXTRA_ZLIB_LIBDIR="-L$with_zlib_libdir"
    fi
    if test "x$with_zlib_include" != x; then
      EXTRA_ZLIB_INCLUDE="-I$with_zlib_include"
    fi
  fi

  OLD_LDFLAGS=$LDFLAGS
  OLD_CPP=$CPP
  OLD_LIBS=$LIBS

  LDFLAGS="$LDFLAGS $EXTRA_ZLIB_LIBDIR"
  CPP="$CPP $EXTRA_ZLIB_INCLUDE"

  if test "$with_system_zlib" = yes; then
    AC_CHECK_LIB(z, inflate,,
      AC_MSG_WARN(Standard ZLIB library not found. Compiling my own.)
      with_system_zlib=no)
  fi

  if test "$with_system_zlib" = yes; then
    AC_CHECK_HEADERS(zlib.h)
    if test "$ac_cv_header_zlib_h" != yes; then
      AC_MSG_WARN(zlib.h not found. Using my own zlib sources.)
      with_system_zlib=no
    fi
  fi

  LDFLAGS=$OLD_LDFLAGS
  CPP=$OLD_CPP
  LIBS=$OLD_LIBS

  if test "$with_system_zlib" != yes; then
    ZLIBCPPFLAGS='-I$(ZLIBSRCDIR)'
    LDZLIB=
    ZLIBDEP=
    using_system_zlib=no
  else
    ZLIBCPPFLAGS="$EXTRA_ZLIB_INCLUDE"
    LDZLIB="$EXTRA_ZLIB_LIBDIR -lz"
    ZLIBDEP=
    using_system_zlib=yes
  fi

AC_SUBST(ZLIBCPPFLAGS)
AC_SUBST(LDZLIB)
AC_SUBST(ZLIBDEP)