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Re: gcc 3.2's cpp breaks configure scripts




> > cpp is spitting out a warning about changing the search order of include
> > directories, and this is breaking a _ton_ of configure scripts. I found
> > this when I started rebuilding Mandrake with gcc-3.2 branch.

Gareth Pearce writes:
> This, from what little i have seen, seems to be due to the fact that many
> configure scripts segments are extremely overly picky. They take any output
> at all as to mean that its failed. Really it should seem to me that they
> should be looking for errors, or specific warnings rather then just anything
> at all.

Just the same, it's a lot to ask the distributors of GNU/Linux and BSD
systems to fix every configure script in the world.
Indeed it would be, but prehaps this should be suggested to the autoconf people for future versions?
Maybe a workaround for the time being is to have a gcc option that
suppresses this one warning; people can then write something like

CC="gcc -Wno-check-include-order" ./configure ...

to get around the problem.

However, if this warning appears, it is likely that the programs in
question won't build properly on OSes that ship bad C headers, that have
to be fixed by fixincludes.  In that case, it may well be that the gcc
command lines will wind up with something like -I/usr/include which means
that the fixed headers will get bypassed.
Yes, would seem (to me at least) a database of where the fixincluded headers came from would allow gcc to substitute them back in when you pass a -I like that. (I dont see any significant performance issue, is there possibility that people Really want to overide the fixincludes? - in which case there could be a -fallow-fixincludes-overide?).
(Also, last time i checked gcc produces that warning for Any directories which are considered internal, rather than Just the direectories where the fixincluded headers came from! - I compile gcc with --prefix=$HOME on my OSF alpha box since i dont have priviledges for /usr or /usr/local - and even though, all the headers in my home directory are entirely from application install, $HOME/include was the biggest cause of warnings i experienced. - I havent compiled much with my latest gcc cvs version yet so maybe that has changed.)

Idealy in my mind - autoconf would make configure scripts that Warn users if such warnings turned up, but ignore them otherwise.

However, I am a humble user, my opinions are from a very limited sphere of use.

Gareth

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