libgcc crossback fails

I build gcc with build==target!=target

For example

Build=x86_64-linux-gnu
Host=x86_64-w64-mingw32
Target=x86_64-linux-gnu



This is what I get from the crossback which is incorrect.  CC=cc makes no sense since cc does not even need to exist. And the sanity check should not for it either. I don't understand why it needs to run test m32 and mx32 for building cross back compiler

checking for suffix of executables...
checking whether we are cross compiling... configure: error: in `/home/cqwrteur/toolchains_build/toolchainbuildscripts/gccbuild/x86_64-w64-mingw32/.gnuartifacts/x86_64-generic-linux-gnu/x86_64-w64-mingw32/x86_64-generic-linux-gnu/gcc/x86_64-generic-linux-gnu/32/libgcc':
configure: error: cannot run C compiled programs.
If you meant to cross compile, use `--host'.
See `config.log' for more details


/home/cqwrteur/toolchains_build/gcc/libgcc/configure --srcdir=/home/cqwrteur/toolchains_build/gcc/libgcc --cache-file=./config.cache --with-cross-host=x86_64-w64-mingw32 --with-gxx-libcxx-include-dir=/home/cqwrteur/toolchains/x86_64-w64-mingw32/x86_64-generic-linux-gnu/x86_64-generic-linux-gnu/include/c++/v1 --prefix=/home/cqwrteur/toolchains/x86_64-w64-mingw32/x86_64-generic-linux-gnu --disable-nls --disable-werror --enable-multilib --with-multilib-list=m32,mx32,m64 --disable-bootstrap --disable-libstdcxx-verbose --with-libstdcxx-eh-pool-obj-count=0 --disable-sjlj-exceptions --enable-libstdcxx-threads --enable-libstdcxx-backtrace --enable-languages=c,c++,lto --program-transform-name=s&^&x86_64-generic-linux-gnu-& --disable-option-checking --disable-year2038 --with-target-subdir=x86_64-generic-linux-gnu --build=x86_64-generic-linux-gnu --host=x86_64-generic-linux-gnu --target=x86_64-generic-linux-gnu build_alias=x86_64-generic-linux-gnu host_alias=x86_64-generic-linux-gnu target_alias=x86_64-generic-linux-gnu CC=cc     CFLAGS=-g -O2 LDFLAGS= CPPFLAGS= --no-create --no-recursion


This is what i get from the canadian build (build!=host==target)

/home/cqwrteur/toolchains_build/gcc/libgcc/configure --srcdir=/home/cqwrteur/toolchains_build/gcc/libgcc --cache-file=./config.cache --with-cross-host=x86_64-w64-mingw32 --with-gxx-libcxx-include-dir=/home/cqwrteur/toolchains/x86_64-w64-mingw32/x86_64-generic-linux-gnu/x86_64-generic-linux-gnu/include/c++/v1 --prefix=/home/cqwrteur/toolchains/x86_64-w64-mingw32/x86_64-generic-linux-gnu --disable-nls --disable-werror --enable-multilib --with-multilib-list=m32,mx32,m64 --disable-bootstrap --disable-libstdcxx-verbose --with-libstdcxx-eh-pool-obj-count=0 --disable-sjlj-exceptions --enable-libstdcxx-threads --enable-libstdcxx-backtrace --enable-languages=c,c++,lto --program-transform-name=s