On 09/23/2010 03:52 PM, Eric Blake wrote:
On 09/23/2010 06:56 AM, Ralf Corsepius wrote:
Hi,
I am facing a new issue/regression with autoconf-2.68:
That is not a regression, but a feature.
Your feature is my regression - It broke what appeared to have worked
for ages ;)
Reread NEWS:
AC_COMPILE_IFELSE([
#ifndef FOO
choke me
#endif
])
You should have used:
AC_COMPILE_IFELSE([AC_LANG_SOURCE([
#ifndef FOO
choke me
#endif
])
OK, thanks.
With older autoconfs, autoreconf remains entirely silent.
Not only were they entirely silent, but most likely generated a broken
configure. If you don't use AC_LANG_SOURCE, then you don't get the
benefit of all the prior AC_DEFINEs being implicitly included before
the body of your test, which leads to documented cases of
mis-diagnosing whether a feature is present for a given build.
Actually, I don't need the AC_DEFINES in this particular case - Adding
them however, should not do much harm, either.
What is wrong with this configure.ac rsp. how to overcome these
warnings?
Use AC_LANG_SOURCE, like the warning told you to do in the first place.
Well, "really usable warnings" look a bit different than this warning.
They might be self-explanatory to you, but to me this warning was "Greek".
Ralf
