Re: Configure tries to run cross-compiled programs (when buildingcrossgcc under cygwin)

[Dan Kegel <dkegel at ixiacom dot com>]

Ralf Corsepius wrote:
> > > > [I'm building a cross-compiler on cygwin targetting x86 linux. ...
> > > > It locks up on "checking whether a program can dlopen itself..."
> > > (see http://gcc.gnu.org/ml/gcc-help/2002-05/msg00165.html )
> > >
> > > I'm running into the exact same thing (I'm trying to build a ppc405
> > > cross-compiler, but the problem is the same).   For reference,
> > > the cygwin gcc I'm using to build this cross-compiler is "2.95.3-5".
> > > ...
> > > in several places, configure tries to run
> > > powerpc programs on windows, and I get an error dialog box.
> The standard autoconf-2.13 check to detect crosscompilation is based on
> trying to run a binary. Win however, sometimes actually _starts_ foreign
> binaries and fails later, instead of refusing to execute foreign
> binaries.
>
> This issue has been fixed/worked around for a long time in newer
> autoconf versions, but gcc still uses autoconf-2.13, so .. it is victim
> of this issue.
Yep.  Figured that out eventually (I post too soon; it's a bad habit).

> > The script works fine on Linux, but fails on Cygwin.
> > One suspicious difference is in gcc-build-ppc405/powerpc-linux/config.cache
> > in Linux, it has
> >  ac_cv_prog_cc_cross=${ac_cv_prog_cc_cross=yes}
> > but in Cygwin, it has
> >  ac_cv_prog_cc_cross=${ac_cv_prog_cc_cross='no'}
> > Now if only I could figure out gcc's configure system...
> > I have no idea what is creating that setting.
> It is the config.cache shared by all configure scripts for the target
> and normally is generated by the first configure script to be run for
> the target.
Yep.  Understand that now.

> You can try to preset the target's config.cache.
>
> Eg. use something like this:
>
> mkdir powerpc-linux
> echo "ac_cv_prog_cc_cross=yes" > powerpc-linux/config.cache
> <pathtosources>/configure --target=powerpc-linux [...]
Thanks!  I'll give it a shot.
- Dan




------
Want more information?  See the CrossGCC FAQ, http://www.objsw.com/CrossGCC/
Want to unsubscribe? Send a note to crossgcc-unsubscribe@sources.redhat.com