cross libstdc++-v3 configuration

[Matthew Jones]

Hello,

I'm trying to build libstdc++-v3 for a cross development system.
Host is i686-pc-cygwin, target system is powerpc-ibm-eabi.
I started out using crosstool, but this failed in libstdc++-v3 with "No support
for this host/target combination."

So now I'm building it by hand, and it seems that no matter which configuration
I try, it always picks up /usr/bin/gcc and determines "checking whether we are
cross compiling... no". I have tried various combinations of --host, --build
and --target. Even after reading libstdc++-v3/configure --help, it is not clear
to me what I need to set.

I am using freshly opened cygwin DOS boxes, so I'm probably not preserving any
environment that crosstool may have set up.

Please could someone explain what I need to do to force it to cross compile ?
Do I need to set a load of environment variables before I run configure?

Thanks,

--
Matthew JONES
http://www.tandbergtv.com/