Yes, we do this in some of the packages already where we pass
ac_cv_lib_foo=no through CONFIGURE_ENV.  The difference between this
and the pkgautoconf stuff is whether we explicitly remove libraries or
if we explicitly allow checks for them.  I think of it as kind of a
"default-allow" versus "default-deny" stance, to borrow firewall
terminology.  I guess we should answer the question of the philosophy
to which we want to adhere in pkgsrc.  I think we should be
"default-deny", meaning we should be required to explicitly name the
libraries we wish to allow to be found.

	Cheers,

     -- Johnny C. Lam <lamj@stat.cmu.edu>
        Department of Statistics, Carnegie Mellon University
        http://www.stat.cmu.edu/~lamj/


Dan Winship <danw@ximian.com> writes:
> 
> On 13 Jun 2001 05:42:48 -0400, Johnny C. Lam wrote:
> > There was a suggestion by Todd Vierling <tv@wasabisystems.com> that we
> > try to hack the AC_CHECK_LIB macro in autoconf as an alternative way
> > to deal with hidden dependencies.
> 
> You don't need to hack the macro. Just fake out the cache:
> 
> danw@twelve-monkeys:/tmp> cat configure.in
> AC_INIT(configure.in)
> 
> AC_CHECK_LIB(c, main)
> AC_CHECK_HEADER(stdio.h)
> 
> AC_OUTPUT(Makefile)
> danw@twelve-monkeys:/tmp> echo ac_cv_lib_c_main=no > config.cache
> danw@twelve-monkeys:/tmp> echo ac_cv_header_stdio_h=no >> config.cache 
> danw@twelve-monkeys:/tmp> ./configure
> loading cache ./config.cache
> checking for main in -lc... (cached) no
> checking how to run the C preprocessor... cc -E
> checking for stdio.h... (cached) no
> updating cache ./config.cache
> creating ./config.status
> creating Makefile
> 
> -- Dan