Can't build libstdc++-v3 for powerpc cross env

[FERANDELLE Pascal]

I try to build a GCC cross environment for C and C++, targeting powerpc-elf.
My host is a PC under Linux Red Hat Enterprise.
I already built the associated binutils 2.15 for the target.
I ran the configuration phase with :

<source_dir>/configure --target=powerpc-elf --enable-languages="c,c++"

then make.

The build stops in the libstdc++-v3 part, during configuration phase, with the message :

Configure: error: No support for this host/target combination
make[1]: *** [configure-target-libstdc++-v3] erreur 1

I tried with source package 3.4.6 and 4.1.0, for the same result.

Any help would be appreciated !!!

Pascal