Re: Build problem with gcc 3.4 on Mac OS X

[Phil Edwards <phil at codesourcery dot com>]

On Fri, Jun 25, 2004 at 07:50:31PM -0700, Jim Wilson wrote:
> Davide Angelocola wrote:
> >checking how to run the C preprocessor... /lib/cpp
> >configure: error: C preprocessor "/lib/cpp" fails sanity check
> >$ grep cpp gcc/config.log
> >/Users/davang/gcc-3.4.0/gcc/configure: line 1: /lib/cpp: No such file or 
> >directory
> >configure:2814: /lib/cpp  conftest.c
> 
> If you look at the gcc/config.log file instead of grepping it, you 
> should see some useful info that might explain the failure.
> 
> configure will try "$CC -E" first, if this doesn't work, then I might 
> wonder if something is wrong with the value of CC in your environment.
> 
> I don't know why /lib/cpp would be used unless perhaps you have the CPP 
> environment variable set to it, but then that begs the question of why 
> that environment variable is set.  It should not be set normally.

It's autoconf, trying to be clever.  Operating systems designed by morons
used to ship the preprocessor as /lib/cpp, so that's what autoconf's
generated script use as a universal fallback if '$CC -E' and other
combinations don't work.

Unfortunately, there's no good way to distinguish between

    $CC -E is not the way to invoke the oreprocessor

and

    $CC -E would be the way to invoke the oreprocessor, but $CC is broken

therefore autoconf always assumes the first is true.

The next step is as Jim wrote:  you need to look in the log file, not just
grep for bits.

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