Gilles Chanteperdrix wrote:
> Heikki Lindholm wrote:
>  > Jan Kiszka kirjoitti:
>  > > Heikki Lindholm wrote:
>  > > 
>  > >>Jan Kiszka kirjoitti:
>  > >>
>  > >>
>  > >>>Hi,
>  > >>>
>  > >>>I'm dumb x86 user who unfortunately just seem to have tumbled in the
>  > >>>cross-compilation trap: I'm trying to generate i586 code on a fancy new
>  > >>>and fast x86_64 compilation host. I got the kernel compiled with
>  > >>>ARCH=i386, using only the pre-installed compiler (i.e. no dedicated
>  > >>>cross tool chain), but I failed to compile xenomai against that kernel
>  > >>>in the following. Which magic switch do I have to apply and where?
>  > >>
>  > >>
>  > >>As dumb a guess: -m32 compiler switch?
>  > >>
>  > > 
>  > > 
>  > > Yes, I know, that would help. But where to feed this argument into the
>  > > build system?
>  > 
>  > I would try makefile (and perhaps config/kconfig/Makefile*) and command 
>  > line 'CC="gcc -m32" CXX="gcc -m32" make menuconfig/install' to be sure.
> 
> When using autoconf, you are not supposed to pass compiler flags in
> CC, CFLAGS and CXXFLAGS are made for that... and the build system is
> supposed to only touch AM_CFLAGS, so that CFLAGS is let for users, but I
> am pretty sure this does not work with Xenomai, since we never tried :-)

Indeed. Setting CFLAGS on make overwrites a lot of important stuff, and
the compilation fails eagerly.

> 
> As for the compilation for pentium on an x86_64, isn't there any
> i686-linux-gcc that directly cross compiles for ia32 ?
> 
> If not, would not the following wrapper do the trick ?
> 
> #! /bin/sh
> exec `expr "$0" : 'i686-linux-\(.*\)'` -m32r ${1+"$@"}
> 
> It should work with most build systems...
> 

Yes, this seems to work (and fail) just like the "CC=" approach.

Jan