Re: configure error ... not set in the previous run

[Ralf Wildenhues]

* John Calcote wrote on Tue, Aug 25, 2009 at 10:46:30PM CEST:
> I've got a friend at work that's experiencing this problem while
> building an apache distribution:
> 
> ...
> utilities/agctl/Makefile.am:16: compiling `agctl.c' with per-target
> flags requires `AM_PROG_CC_C_O' in `configure.in'
> Makefile.am: installing `./INSTALL'
> Running autoconf ...
> Running ./configure --config-cache --enable-maintainer-mode
> --enable-compile-warnings --with-apache=/opt/novell/apache2
> --prefix=/opt/novell/access-manager
> --sysconfdir=/etc/opt/novell/access-manager --libdir=/opt/novell/lib
> ...
> configure: WARNING: unrecognized options: --enable-compile-warnings
> configure: loading cache config.cache
> configure: error: `CFLAGS' was not set in the previous run
> configure: error: in `/usr/src/packages/BUILD/novell-apache-gateway-1.0.0':
> configure: error: changes in the environment can compromise the build
> configure: error: run `make distclean' and/or `rm config.cache' and
> start over
> error: Bad exit status from /var/tmp/rpm-tmp.91236 (%build)
> 
> He's wondering (and so am I) what the error, "configure: error:
> `XYZ' was not set in the previous run" means.

Your friend is using a cache file file (config.cache) that saves the
results from a previous configure run.  Now the CFLAGS that are passed
to the configure invocation have changed, and configure "knows" (by
means of CFLAGS being a precious variable) that the cached results could
be wrong for this CFLAGS setting (imagine adding -m32, -m64, or so).
See 'info Autoconf "Setting Output Variables"'.

Note that it is possible that you did not enable the caching yourself
but apache's build machinery did, and it is possible that that same
build machinery munges CFLAGS before passing it to configure.  In that
case it indicated a bug in that machinery.

Cheers,
Ralf