Re: AC_TRY_COMPILE() annoyances with 2.63b

[Mike Frysinger]

On Sunday 05 April 2009 20:46:03 Eric Blake wrote:
> According to Mike Frysinger on 4/5/2009 4:10 PM:
> > AC_TRY_COMPILE() is invoked with an empty 4th argument: [].  i think
> >
> >     [ sp_expire_available=yes ], []
> >     )
>
> That's not an empty fourth argument.  Remember, trailing space IS
> significant, and only leading space is stripped.  The bug is in your
> configure.ac.

it isnt my code.  i have nothing to do with openssh.  i'm merely forwarding 
along regression reports of 2.63b compared to every version previous.  even if 
you decide to keep this behavior, it should be noted in the NEWS.

> That said, autoconf could probably be taught that, for some macros, an
> argument of all whitespace is morally equivalent to an empty argument.
> Patches welcome.

i'm not an expert by any means with internal autoconf/m4.  if there's a m4 
helper function to test whether an argument contains something other than 
whitespace, then the change to m4sh.m4:_AS_IF is trivial ... use that rather 
than m4_ifvaln([$1],....
-mike