$ ./configure --prefix=/home/pure/gcc-4.6-20101106 --disable-bootstrap CFLAGS="-g3 -O0 -pipe -m64" --enable-languages=c,c++
$ make -j6
 ...
 ...
 ...
/usr/bin/ld: skipping incompatible //usr/lib/libc.so when searching for -lc
/usr/bin/ld: skipping incompatible //usr/lib/libc.a when searching for -lc
/usr/bin/ld: cannot find -lc
collect2: ld returned 1 exit status
make[4]: *** [libgcc_s.so] Error 1
make[4]: Leaving directory `/home/pure/Downloads/gcc-4.6-20101106/x86_64-unknown-linux-gnu/32/libgcc'
make[3]: *** [multi-do] Error 1
make[3]: Leaving directory `/home/pure/Downloads/gcc-4.6-20101106/x86_64-unknown-linux-gnu/libgcc'
make[2]: *** [all-multi] Error 2
make[2]: Leaving directory `/home/pure/Downloads/gcc-4.6-20101106/x86_64-unknown-linux-gnu/libgcc'
make[1]: *** [all-target-libgcc] Error 2
make[1]: Leaving directory `/home/pure/Downloads/gcc-4.6-20101106'
make: *** [all] Error 2