Go to: ftp://alpha.gnu.org/pub/gnu/autoconf/ And download autoconf-2.57a. Yes, I know it's an alpha version. Yes, I know it hasn't been updated since June 20th. But I'm not an autoconf developer, so don't blame me. > -----Original Message----- > From: Daniel Jacobowitz [mailto:drow@xxxxxxxxx] > Sent: Thursday, September 11, 2003 10:49 AM > To: autoconf@xxxxxxx > Subject: Re: Bugs encountered updating GCC > > On Sun, Sep 07, 2003 at 02:07:51PM -0400, Daniel Jacobowitz wrote: > > Hi autoconf'ers... > > > > I've been involved in converting a number of projects in the GCC and > sources > > (binutils, gdb, etc) repositories to autoconf 2.57. By and large, it's > > going well, but we've turned up a couple of problems. I'm not familiar > with > > autoconf development, so these may have more historical baggage than I > know > > about... > > > > The first is with AC_CHECK_HEADERS. The manual says: > > Previous versions of Autoconf merely checked whether the header was > > accepted by the preprocessor. This was changed because the old test was > > inappropriate for typical uses. Headers are typically used to compile, > > not merely to preprocess, and the old behavior sometimes accepted > > headers that clashed at compile-time. > > > > However, that's not the whole story. The old check also failed if there > > were warning messages on stderr when preprocessing. The new one doesn't > do > > that, by default. Instead it only does so if ac_c_preproc_warn_flag, > which > > is only set if missing headers are a warning rather than an error. As a > > result autoconf now decides malloc.h is available on FreeBSD, even > though it > > has a #warning in it. > > > > Test case: > > foo.h: > > #warning "A.h" > > > > configure.in: > > AC_INIT(foo.h) > > AC_CHECK_HEADERS([foo.h]) > > AC_OUTPUT > > > > Old output: > > configure:609: checking for foo.h > > configure:619: gcc -I/home/drow/autoconf/o/.. -E conftest.c >/dev/null > 2>conftest.out > > In file included from configure:615: > > /home/drow/autoconf/foo.h:1:2: warning: #warning "A.h" > > configure: failed program was: > > #line 614 "configure" > > #include "confdefs.h" > > #include <foo.h> > > > > > > configure:2606: checking foo.h usability > > configure:2619: gcc -I/home/drow/autoconf/o/.. -c -g -O2 conftest.c >&5 > > In file included from configure:2660: /home/drow/autoconf/foo.h:1:2: > warning: #warning "A.h" > > configure:2622: $? = 0 > > configure:2625: test -s conftest.o > > configure:2628: $? = 0 > > configure:2638: result: yes > > configure:2642: checking foo.h presence > > configure:2653: gcc -I/home/drow/autoconf/o/.. -E conftest.c > > In file included from configure:2662: /home/drow/autoconf/foo.h:1:2: > warning: #warning "A.h" > > configure:2659: $? = 0 > > configure:2678: result: yes > > configure:2714: checking for foo.h > > configure:2721: result: yes > > Any comments on this? > > I can work around it by conditionally putting -Werror into CPPFLAGS, > but I don't really like that; I'm not sure what else it might do to > configure. Both compiler warnings and errors used to be fatal and now > neither of them seem to be. > > -- > Daniel Jacobowitz > MontaVista Software Debian GNU/Linux Developer > >
